Food product surface sterilization apparatus and method

ABSTRACT

An apparatus is disclosed for the micro-organism surface sterilization of foods using, a “germicidal” such as light waves (e.g., ultraviolet), and in some cases in combination with (or replaced by) one or more of sound waves and ozone. The surface sterilizer apparatus may include a plurality of germicidal (e.g., ultraviolet) emitters for surface sterilization of foods that are, e.g., rotated in a drum or rotated via a screw auger. Assemblies of emitters for the germicidal may be constructed to be watertight (i.e., withstand a high pressure, heated water spray), and movable relative to the drum or screw conveyor for easy cleaning and maintenance. The apparatus may also include a controller (e.g., programmable logic controller) for controlling the sterilization process so that the apparatus does not endanger personnel nearby, and so that the food is properly sterilized. The controller may vary the amount of germicidal used, the rate that food traverses the apparatus, the inclination of the apparatus, and terminate sterilization processing when an unsafe condition is detected. The apparatus may be used in-line with other food processing equipment for the real-time sterilization of food. The controller may also communicate with food processing components upstream of the apparatus for controlling the flow of food to the surface sterilizer

RELATED APPLICATIONS

[0001] The present application claims the benefit of, and incorporatesfully by reference, each the following: U.S. Provisional PatentApplication Serial No. 60/393,792 filed Jul. 3, 2002; U.S. ProvisionalPatent Application Serial No. 60/393,363 filed Jul. 3, 2002; and U.S.Provisional Patent Application Serial No. 60/449,725 filed Feb. 24,20034.

RELATED FIELD OF THE INVENTION

[0002] The present invention relates generally to the field ofsterilization equipment, and, more specifically, to a device for surfacesterilization of foodstuffs of various regular or irregular shapes, thisdevice includes a combination of germicidal radiation, ozone and adevice for rotating and conveying the foodstuffs such as (a) a rotatingdrum that lifts, tumbles, and advances the foodstuff within the drum inthe presence of the germicidal radiation, and (b) a screw conveyor thatlifts, tumbles, and advances the foodstuff within the screw conveyor inthe presence of the germicidal radiation and/or ozone. Foodstuffsmentioned here mean edible products and ingredients that should besterilized because of public health.

BACKGROUND OF THE INVENTION

[0003] Various processes have been used to sterilize foodstuffs. Thermalprocessing of foodstuffs so that they will be safe for consumption isused in a variety of forms. For example, foods are commonly sterilizedand preserved by commercial canning processes in which a food product isplaced in a hermitically sealed container and then heat processed. Forfruit and vegetable products, the canning process alters the flavor andtextural qualities of the food product. An alternative to the canningprocess for vegetables is the blanch frozen process, in which freshvegetables are thermally processed in the blanching process toinactivate enzymes, then frozen for preservation of the vegetables. Inwater blanchers, the water is typically chlorinated to provide surfacesterilization of the vegetables. Some vegetables, such as French friedpotatoes, are blanched and partially fried prior to freezing forpreservation. For fresh fruits and vegetables, the food product (alsodenoted herein as “foodstuff”) is typically washed in chlorinated orother chemically treated water to destroy surface bacteria. In cookedmeat products, the food product is cooked to a temperature sufficient todestroy microorganisms, then chilled or frozen for preservation of thecooked meat product. In dry foodstuffs such as nuts and grains, suchfoodstuffs are bathed in an atmosphere or solution of chemicals that aretoxic to microorganisms (e.g., yeast, mold spores, fungi), and the eggand/or larva of insects. However, the chemicals used are costly and mayleave a residue, which can be ingested by the consumer. Moreover, suchchemical treatments are not always effective in view of the numerousinstances of live and dead insects and mold still encountered inpackaged dry foodstuff products.

[0004] In foodstuffs which are frozen for preservation, such as blanchedvegetables, partially fried potato products, and cooked meat products,the thermal or chemical bacteria kill process is prior to the freezingand packaging of the foodstuffs. In the freezing and packagingprocesses, the probability of surface re-contamination of the foodstuffexists. Processors of these products regularly test the frozen productsfor microorganisms resulting from surface contamination. Products withcontamination are either sent to waste, or reprocessed to againthermally or chemically kill the microorganisms.

[0005] It is well known that ultraviolet radiation, particularlyultraviolet radiation having a wavelength of approximately 254nanometers (nm), and more generally, in the range of 235-280 nm (suchradiation denoted herein as “UVC”), kills microorganisms includingyeast, mold spores, bacteria, fungi, as well as the eggs and/or larva ofinsects. In the August, 2000 issue of “Meat & Poultry” magazine, anarticle by Richard Stier (entitled “Shedding some light. Pulsed LightSterilization—a Tool for the Future”, pages 60 through 63, hereinincorporated fully by reference) includes dosage quantities inmilliwatt-seconds per square centimeter to achieve 90% kill of commonbacteria, mold spores, and viruses. In the February, 1996 issue of“Heating/Piping/Air Conditioning” magazine, an article entitled “UsingUVC Technology to Enhance IAQ”, (herein incorporated fully by reference)by Robert Scheir, PhD and Forrest B. Fencl define UVC germicidal energyrequired to achieve 90% kill of common microorganisms for bacteria,yeasts, and mold spores.

[0006] Many mechanisms have been devised which use ultraviolet radiationfor the protection of foods, pharmaceuticals, and other productsaffected by microorganisms and/or insect eggs/larvae. Some referencesdisclosing foodstuff sterilization techniques that have been attemptedare as follows (these references being fully incorporated herein byreference):

[0007] (a) U.S. Pat. No. 6,132,784 filed Feb. 19, 1999 by Brant et. al.(incorporated fully by reference herein) describes a method andapparatus in which round fresh fruits and vegetables are conveyed on aconveyor with rotating rollers that subsequently rotate the round fruitor vegetable in the presence of an overhead UVC germicidal light source.This apparatus is limited to products, which have a shape that is roundor spherical, and smooth.

[0008] (b) U.S. Pat. No. 4,776,267 filed Mar. 25, 1987 by Harris(incorporated fully by reference herein) describes an apparatus in whichthe foodstuffs are transported on a shaker table to spread out the flowof the foodstuff in the presence of an overhead UVC germicidal lightsource. This apparatus includes two product turnovers as compared to thepresent invention which continuously tumbles and turns the foodstuff,increasing the probability that all surface area is adequately exposedto the UVC germicidal light source.

[0009] (c) U.S. Pat. No. 5,958,336 filed Apr. 26, 1996 by Duarte(incorporated fully by reference herein) describes an apparatus in whichobjects are conveyed with UVC germicidal light sources above and belowthe conveyor. This apparatus has the disadvantage of the potential ofshadowing, which reduces the probability that all surface areas areexposed to the UVC germicidal light source. This apparatus is for thesurface sterilization of containers, which enter the “clean room” forthe packaging of pharmaceutical products.

[0010] (d) U.S. Pat. No. 6,171,548 filed Nov. 16, 1998 by Rose et. al.(incorporated fully by reference herein) describes a method andapparatus for sterilizing organic and inorganic matter throughsimultaneous exposure to ultraviolet light energy and ultrasonic waveenergy in a non-aqueous environment such as air. The apparatus is eithera chamber or a conveyor belt. This apparatus has the disadvantage of notcontinuously tumbling and turning the product to be sterilized, thusreducing the probability of exposing all surfaces to the ultravioletlight energy.

[0011] (e) U.S. Pat. No. 4,983,411 filed Aug. 24, 1989 by Tanka teachesvacuum packing raw meat in a UV transmissible film, exposing the vacuumpacked meat in its package to ultraviolet irradiation, and thenshrink-wrapping the package around the raw meat in a high temperatureatmosphere. Tanaka uses broad-spectrum UV-radiation, includinglong-wavelength radiation (300 nm and greater). Such radiationpenetrates packaging film relatively easily but may not be veryeffective at impairing or killing microorganisms. Any such activity islikely to be non-specific, e.g. relying largely on a heating effect.Moreover, such irradiation may have deleterious effects on meat quality,e.g. associated with photochemical oxidation of lipids and/or pigments.Note that the present application addresses the sterilization of afoodstuff prior to packaging, and is applicable to products of varioussizes wherein if packaged prior to sterilization, various productsurfaces can be shadowed or unexposed inside the package. That is,Tanka's technique of treating a product with a surface sterilizing agentafter packaging is only effective on those surfaces that are exposedthrough the packaging material.

[0012] (f) U.S. Pat. No. 5,597,597 filed Feb. 23, 1995 by Newmandiscloses a stationary “irradiation tunnel” surrounding a “supportmeans” (e.g., a conventional conveyor, or a drum conveyor), wherein afoodstuff in the tunnel is exposed to UV. Various techniques aredisclosed for presumably irradiating all sides of a foodstuff with ansufficient UV light “for reducing the microbial load, e.g. onfoodstuffs, especially fresh and processed meats.” However, thedisclosed apparatus has the following drawbacks:

[0013] (i) The conveyor embodiments require that the product items beingirradiated not be stacked on one another or bunched together on theconveyor. Thus, some mechanism must assure the product items are spacedapart prior to the product items entering the irradiation tunnel.

[0014] (ii) The conveyor embodiments require some means of appropriatelyirradiating the product surfaces in contact with the conveyor. It isstated that a “wide mesh for the conveyor is preferred as this willminimize contact points between the foodstuff and the conveyor.”However, the width of the mesh must be sufficiently smaller than thefood product items being irradiated to retain the product items on theconveyor. Thus, for food products of substantially different sizes(e.g., shrimp or nuts versus steaks), the conveyor belt may have to bereplaced with one of a different mesh, or alternatively, the conveyormay have a very fine mesh (for accommodating virtually any product), butthen creating more product surface area that is not appropriatelyexposed to the surface sterilization agent. Additionally, in onedisclosed embodiment, “guides or baffles” are disclosed for shifting theproduct items while resting on the conveyor”. Note, however, that theaction of such guides pushing the product against the friction on theconveyor belt may cause damage to fragile products. In anotherembodiment, multiple conveyors serially convey the product items throughthe tunnel wherein the product support belt for the conveyors have adifferent pattern contacting the product items. Numerous transfers ofthe product may be required to assure that all surfaces on irregularshaped free flowing products are treated (as compared to the rotatingtumbling drum or screw conveyor with lifting baffles of the presentinvention). In yet another embodiment, there is a suggestion that theconveyor belt itself be made of a UV transmissive material. However, itis unclear how such material would maintain such a UV transmissivequality in a commercial food product setting without becomingsubstantially opaque due to residue build up and/or abrasion orscratching. Moreover, even if an appropriate UV transmissive conveyorcould be provided, products near the center of the conveyor may not havetheir surfaces adequately exposed to the UV radiation due to theshadowing of adjacent product items.

[0015] (iii) In the drum conveyor embodiments, the UV lights arepositioned about the exterior of a rotatable drum conveyor. The drumconveyor is disclosed as being of “a simple grid structure” wherein thediameter of the mesh of the grid forming the walls of the drum aredetermined by the size of the product items to be irradiated.Accordingly, the drum mesh may preclude a substantial amount of the UVradiation from contacting the product items when, e.g., the productitems are small and/or the drum grid must withstand a considerableproduct load (e.g., thousands of pounds). The shadowing of the mesh drumis proportional to the percent open area of the mesh as compared to thepresent invention where the UV lights are positioned inside the rotatingdrum or screw conveyor with lifting baffles, and has no shadowing on theproduct being treated with the exception of shadows created by theproduct itself. Moreover, the positioning of the UV lights appearsproblematic (e.g., at least those below Newman's drum, and possibly alsothose above the drum, depending on the drum rotational speed) forproduct items that cast off dirt, debris or any liquid (e.g., water) inthat the UV lights will become progressively less light transmissiveunless the sterilization process is repeatedly stopped so that lightscan be cleaned.

[0016] Thus, it would be desirable to have a food sanitizing method andapparatus that could cost effectively be used in most commercial foodprocessing facilities that need to reduce the microbial population onthe surface of food products, wherein the method and apparatus did nothave the disadvantages of the prior art as described above. Inparticular, it would be desirable to have a method and apparatus forsterilizing food products: (a) in high volume, wherein the amount(volume, or weight) of the product to be sterilized is large, (b) wherethe food product items vary substantially in size and shape, and (c)where the apparatus does not require a specialized environment, e.g., aclean room. Moreover, it would be desirable to have a food sanitizingapparatus that can be safely cleaned by the conventional high pressureand high temperature washing cleaning techniques used in commercial foodprocessing facilities. More particularly, when ultraviolet emitters areused as the sterilizing agent, it would be especially desirable to haveprotective shielding surrounding such emitters so that there isvirtually no possibility of UV emitter materials (e.g., glass)commingling with the food product being sterilized and/or failing due tothe high pressure, high temperature cleaning techniques used.

OBJECTS OF THE INVENTION

[0017] An object of the present invention to sterilize foodstuff so thatit is safe for human consumption.

[0018] It is a further object of the present invention to providesurface sterilization without the use of foodstuff altering chemicals.

[0019] It is an additional object of the present invention to surfacesterilize free flowing frozen foodstuff without the thawing of thefrozen foodstuff. In particular, it is as object of the presentinvention to sterilize food products that may have substantial portionsof their surfaces encased in ice. Moreover, the present invention isparticularly well suited for decontaminating and/or sterilizing freeflowing, fresh, dry, or individually quick frozen, particulate foodproducts. Such dry products include, e.g., grains, nuts, rice, cereals,crackers, dehydrated products, potato chips, corn chips, etc.Individually quick frozen products include corn, peas, carrots,potatoes, French-fried potatoes, beef crumbles, fajita meats, etc. Freshproducts include potatoes, carrots, beans, onions, fruits, etc.

[0020] It is also an object of the present invention to sterilizefragile foodstuff in which food product breakage creates waste.Accordingly, the present invention is applicable to raw vegetableproducts, which have surface bacteria, molds, and fungi existing as theyare harvested from farm locations and intended for processing operationsor storage facilities for future processing.

[0021] It is also an object of the present invention to surfacesterilize foodstuffs in mass production food processing plants whichrequire protection from glass or other items from commingling with thefoodstuffs. Accordingly, it is an object of the invention to providewatertightness to those components of the invention that could be easilydamaged or break with exposure to high pressure and high temperaturewater sanitizing procedures of mass production food producing plants. Inparticular, such components may include: light assemblies, machinecontrols and electronics, and safety features required to operate withingovernmental regulatory requirements.

[0022] Terms and Definitions

[0023] Germicidal: As a noun this term denotes one or a combination of:a radiation energy (e.g., ultra-violet), and a substance such as ozone(possibly in combination with certain “enhancers” such as intenseacoustic waves for exciting molecules on the surface of a food productthereby increasing the effectiveness of a sterilizing agent such asultraviolet radiation on killing layered bacteria cultures) that can beapplied to the surface of food products wherein there is asterilization, sanitation, decontamination and/or disinfecting of thefood product surface so that subsequently the food products can besafely consumed by humans or animals, and wherein such a germicidal doesnot substantially penetrate or modify the foodstuff to which it isapplied. The “germicidal” as used here refers to a process and/or anoutput from a process for reducing (and preferably killing)micro-organisms (e.g., bacteria, viruses, fungi, molds, and/or spores)that reside on a surface of a food product, wherein such micro-organismscould compromise the safety, shelf life, appearance, nutrition, smell,taste, and/or texture of a food product. More particularly, a germicidalmay be selected wavebands of ultraviolet light to inactivate one or moremicro-organisms by inducing photochemical changes in the micro-organismswhich render them unable to duplicate or transport and metabolizenutrients essential for their survival. The wavelength of ultravioletlight which is most effective for inactivating micro-organisms is lessthen about 310 nm and more particularly between about 250 nm and about280 nm.

[0024] UV: This term denotes ultraviolet light in a range ofapproximately less than 310 nm.

[0025] UVC: This term denotes ultraviolet light in the C band; i.e.,ultraviolet radiation having a wavelength in a range of approximately220 to 290 nanometers (nm), and more particularly approximately 250 to280 nm, and even more particularly approximately 265 nm. The followingtable shows the relative effectiveness of various ultraviolet wavelengths on micro-organisms, wherein a relative germicidal effectivenessof 0.60 for a first wave length means that it is generally about half aseffective as a second wave length having a relative germicidaleffectiveness of 1.20. TABLE 1 Germicidal effectiveness. Relative Wavelength, germicidal nm effectiveness 240 0.62 245 0.76 250 0.90 255 1.03260 1.12 265 1.15 270 1.08 275 0.98 280 0.87 285 0.73 290 0.60

[0026] UVC Light Assembly: This term denotes an ultraviolet emitterassembly that includes one or more UVC light emitters. The UVC emittersare sleeved (i.e., encapsulated individually, as an assembly of aplurality emitters, or both) with a UVC transmissive plastic shield. Theultraviolet emitter assembly includes the emitters, a power supply orballast for supplying electrical power to the emitter(s), and a UV lightreflector. The assembly is constructed to with stand high pressure, hightemperature washing activities common to food processing facilities.

[0027] Free flowing food product: This term denotes a food product orfoodstuff that flows substantially as a liquid or granular substancewhen a force is applied thereto for, e.g., conveying the food productbetween destinations.

[0028] Flight(s): For a helixical disk-like structure that winds aroundand extents the length of an auger shaft, the term “flight” refers to aportion of the disk-like structure that winds 360 degrees around theauger shaft in a helical fashion. Thus, typically, an auger has aplurality of such flights continuously flowing into one another as theywind around the auger shaft's length so that when the shaft is rotated,the flights urge the foodstuff in the space between adjacent flights ofthe auger from an auger foodstuff input to an auger output.

[0029] Lifting Tumbler: This term refers to a projection extending froma foodstuff contacting surface wherein this surface is used for rotatingand conveying the foodstuff. Such projections are used for lifting andtumbling, and generally exposing various surfaces of the foodstuff to agermicidal. In particular, such a lifting tumbler may be provided on theinside surface of a drum for supporting and/or lifting a foodstuff whileit is being moved, e.g., by an inclination of the drum, or by a helicalribbon in the drum, or both. In another embodiment, such liftingtumblers may extend from a surface of an auger flight for supportingand/or lifting a foodstuff while it is being moved by the auger througha screw conveyor. Accordingly, when the foodstuff is no longer supportedby such a lifting tumbler, the foodstuff may fall or tumble into a lowerportion of the surrounding foodstuff container (e.g., a drum or auger).Thus, by providing a plurality of such tumblers on the inside surface ofa foodstuff container (e.g., a drum or auger), substantially all thefoodstuff surfaces may be expected to come in contact with asufficiently dosage of a germicidal to sterilize or decontaminate atleast the surface of the foodstuff within the container.

[0030] Exposure Cycle Time: This term denotes the a desired duration ofexposure to a given intensity, I, of radiation (e.g., UVC) divided bythe percentage of efficiency of this intensity that is actually used forsuch exposure. For example, if the desired duration of exposure is 6seconds at an intensity of I₀, and the actual exposure is 50%, then theexposure cycle time is a 12 second cycle time (=6 seconds/50% exposureefficiency).

[0031] Watertight: This term refers to the capability of variousassemblies and subassemblies of the present invention to withstandwithout leakage, failure or reduced effectiveness water sprays, whereinsuch sprays have water pressures of in a range of 1,000 psig to 1,400psig, and more preferably 1,100 psig to 1,350 psig, and most preferablyapproximately 1,250 psig (pounds per square inch gage), and temperaturesup to 210 degrees Fahrenheit (F), and more preferably in a range of 190(F) to 200 (F) and most preferably approximately 195 (F).

SUMMARY OF THE INVENTION

[0032] The present invention is directed to an apparatus for applying toa foodstuff a “germicidal” as defined hereinabove. In particular, thepresent invention (denoted a “surface sterilizer” herein) applies such agermicidal to a foodstuff (equivalently “food product” herein) that isbeing rotated and/or tumbled by at least one rotatable component so thatsubstantially all surfaces of the foodstuff are exposed to thegermicidal. More particularly, during the rotating or tumbling of thefoodstuff, the present invention may transport the foodstuff in aconduit or container (more generally, a “transport”) wherein: (a) thefoodstuff enters the transport at a first location, (b) the foodstuff issterilized while moving through the transport, and (c) subsequently thefoodstuff exits the transport at a second location after beingsterilized. In some embodiments, the transport may be a rotating drum(e.g., as the rotatable component), wherein the foodstuff enters one ofthe drum ends (generally while the drum is rotating) and exits the otherend of the rotating drum sterilized. In other embodiments, the transportmay be an auger trough, wherein a screw type auger (as at least aportion of the rotating component) is provided in the transport formoving the foodstuff from the transport entry to the transport exit.Thus, embodiments of the present invention are well suited for thegenerally continuous type of food product sterilization desirable inhigh volume food processing facilities, wherein, e.g., individual unitsof a food product being concurrently sterilized will have commenced thesterilization process at substantially different times and will exit thesterilization process at substantially different times.

[0033] It is an aspect of the surface sterilizer of the presentinvention that as the foodstuff transverses the transport, the foodstuffis rearranged and reoriented in the transport so that there is asubstantially uniform exposure to all surfaces of the foodstuff by thegermicidal. Accordingly, the surface sterilizer may include variousfoodstuff supports that generally rotate within the transport. Thesesupports (denoted herein as “tumblers”) at least partially support thefood products so that the food products are carried a greater extentupwardly, as the foodstuff progresses through the transport, than wouldotherwise occur without the tumblers. In particular, it is an aspect ofthe invention that such tumblers may be configured so that most orsubstantially all of the individual food product items tumble downwardlyover (or under) a boundary for the food product support surfaces of thetumblers thus substantially assuring that individual food products haveall their surfaces exposed to a sterilizing concentration of thegermicidal. That is, the rotationally upwardly carried food productsgenerally tumble (e.g., over or under a tumbler edge) from their tumblersupports when the supports reach an upwardly inclined positionsufficient for the food products to tumble off. Thus, such tumblingcauses the food products to be rearranged and reoriented for moreuniform exposure to the germicidal.

[0034] In one embodiment, the tumblers may be positioned parallel to therotational axis of the foodstuff being rotated by the rotationalcomponent(s) (e.g., a drum or an auger shaft) of the surface sterilizer.In another embodiment, the tumblers are oriented at an angle to therotational axis of such a rotational component in which case the liftingtumblers may be angled to assist with (and/or somewhat inhibit) themovement of the food product through the trough. However, regardless oftheir orientation to the axis of rotation, the tumblers may beconfigured so that substantially all of the individual food productstumble over (or under) the tumbler boundaries as described above.

[0035] It is also an aspect of at least one embodiment of the invention,that the tumbling action provided by the tumblers be gentle on thefoodstuff or food product. In particular, it is preferred that thetumblers create a rolling motion of the food product instead of a freefalling of the food product. Moreover, such tumblers may include variousconfigurations of openings through which the food product can flow. Inparticular, portions of the food product that are buried may be able toexit one or more of these tumbler openings, e.g., when a rotating drumis used, such openings may be near where a tumbler attaches to theinterior of the drum. Accordingly, such buried portions of the foodproduct become more readily exposed to the UVC germicidal while theupper food product layers are being further lifted by the tumblers.

[0036] Embodiments of the present invention are especially suited tosurface sterilization of large amounts (of weight or volume) of afoodstuff or food product. In particular, when sterilizing largefoodstuff amounts in a continuous manner, embodiments of the inventioninclude sensors and controllers for: (a) monitoring the amount offoodstuff within the transport, (b) increasing or decreasing the amountof foodstuff entering the transport, (c) increasing or decreasing thegermicidal within the transport, and (d) starting foodstuff movement andsterilization within the transport when it is determined that it is safefor food sterilization to proceed and stopping foodstuff movement andsterilization within the transport when it is determined that it isunsafe for food sterilization to proceed.

[0037] In one embodiment, the present invention is particularly wellsuited for free flowing, fresh, dry, or individually quick frozen,particulate cooked or processed food products. Dry food products includespices, herbs, grains, nuts, rice, cereals, crackers, dehydratedproducts, potato chips, corn chips, pork rinds, beef jerky, etc.Individually quick frozen food products include corn (e.g., frozenkernel corn), peas, carrots, whole potatoes, dehydrated potatoes, figs,peppers, French-fried potatoes, beef crumbles, beef trimmings, fajitameats, shrimp, etc. Fresh food products include potato dices and shreds,carrots, asparagus, broccoli, cauliflower, onions, brussels sproutscorn, peas, cucumbers, lettuce, beans, grains, beef, chicken, fish,shrimp, herbs, fruits, blueberries, cranberries, peeled and unpeeledtomatoes, etc.

[0038] The invention described herein may use an ultraviolet light in aC band (i.e., UVC as defined above) as a germicidal, but the inventionis not limited to this germicidal. Thus, other germicidals are alsowithin the scope of the invention such as ozone and/or combinations ofindividual germicidals. The source of the germicidal may be mounted in afixed position for providing a disinfecting exposure of a substantiallyfree flowing foodstuff (e.g., corn, peas, carrots, potatoes,French-fried potatoes, onions, beef crumbles, fajita meats, potatoes,carrots, lettuce, beans, fruits, herbs, spices, beef trimmings, beefsteaks, chicken, shrimp, fish, tomatoes, etc) or tumbleable largerfoodstuff (e.g., broccoli, and/or cauliflower).

[0039] A germicidal UVC light source may include a plurality UVCemitters, wherein each emitter is encased and/or coated with a plasticUVC transmissive sleeve to prevent the potential of glass contaminationof the food product in the event one of emitters shatters. In somepreferred embodiments, the UVC light source or assembly is watertightand able to withstand commercial food processing wash down activitieswhere the UVC light assembly may be exposed to water pressures of 1,250psig (pounds per square inch gage), and temperatures up to 195 degreesFahrenheit without damage or reduced sterilization effectiveness.Moreover, the UVC light assembly may be moveably mounted on a track orhinged on a side so that the assembly can be easily accessed formaintenance (e.g., replacing UVC emitters).

[0040] Furthermore, at least when the transport includes a rotatingdrum, the UVC light assembly may be provided within the rotating drum.In at least some embodiments, the light assembly is generally suspendedin the hollow central volume of the drum so that the light assembly doesnot come in contact with the foodstuff in the drum. Additionally, thelight assembly may be offset from the rotational axis of the drum sothat the UVC light shines more directly and/or intensely on the angularsections of the drum's interior wherein the foodstuff is expected tocongregate during drum rotation. Moreover, since embodiments of the drummay rotate in either or both rotational directions, the UVC lightassembly may be mounted so that the UVC light can be directed to variousangular sections of the drum's interior depending on, e.g., the rotationof the drum. Furthermore, to assist in uniformly distributing theemitted UVC across the exposed surface of the foodstuff in the drum, theUVC emitters may be distributed in the light assembly along an arc thatparallels the circular contour of the drum interior.

[0041] In one embodiment, the drum may be oriented for rotation aroundan axis that is inclined, wherein there is a foodstuff inlet opening onthe upper (higher) axial end, and a foodstuff discharge opening at thelower axial end. The drum may include tumblers inside the drum, and inparticular, on the interior surface of the drum, wherein such tumblerslift and redistribute (tumble) the food products within the drum whilethe drum is rotating. Additionally, in one embodiment, the tumblers(also denoted “lifting tumblers” herein) may be configured for advancingthe food products toward the discharge opening (i.e., drum exit), or inanother embodiment, somewhat inhibiting the movement of the food producttoward discharge opening. Note that tumblers for both advancing andinhibiting the flow of the food product may be included in the sameembodiment of the invention.

[0042] In some drum embodiments of the invention, the tumblers provide aradial variation on the interior surface of the drum whereby: (a) foodproducts within the rotating drum are at least partially supported on aradially inwardly projecting portion of a tumbler (alternatively,supported on a radially outwardly extending drum recess) so that thefood products are carried a greater extent upwardly as the drum rotatesthan would otherwise occur, and (b) the upwardly carried food productsgenerally tumble (over or under) from their tumbler support when thecorresponding rotating interior portion of the drum reaches an upwardinclining tangential angle from the horizontal of 30 degrees to 60degrees.

[0043] In one embodiment of the surface sterilizer where such arotational component is a rotating drum, a helical ribbon (e.g., with acenter axis coincident with the drum rotational axis) can be attached tothe interior circumference of the drum to aid with product movementthrough the drum. Note that such a helical ribbon can be considered anembodiment of the tumblers assuming, e.g., that the individual foodproducts tumble over them and do not substantially only slide over theinterior surface of the drum. However, such a helical ribbon can used inconjunction with other configurations of tumblers to further assist inthe tumbling of the food product.

[0044] In an alternative embodiment, the foodstuff being decontaminatedor sterilized may be conveyed into an inlet of a screw conveyor thatincludes an auger trough and a screw type auger as mentioned above. Sucha screw conveyor is commonly used in the food processing industry forconveying food products as one skilled in the art will understand,wherein the trough supports the foodstuff while it is being moved by theauger within the trough. The auger includes a rotatable auger shaftabout which, e.g., a continuous helical disk-like projection fixedlyencircles the shaft for moving the foodstuff along the trough. Inparticular, such a helical disk may wrap around the auger shaft aplurality of times, wherein the food product is moved through the augertrough in food portions residing between consecutive opposing helicaldisk surfaces (known as “flights” and further described in thedefinitions section above). Embodiments of the surface sterilizerincluding a screw conveyor further include a germicidal emitter thatsterilizes the surfaces of the foodstuff being transported and tumbledwithin the trough. In particular, the germicidal emitters may bepositioned above an upwardly facing open portion of the trough so thatthe germicidal contacts at least surfaces of the foodstuff that are in adirect line of sight with the germicidal emitters. Thus, when thegermicidal includes UVC, the germicidal (UVC) emitters are provided in aUVC light assembly mounted so that the UVC shines into the trough. Insome embodiments, when the trough is open along its length (e.g., thetrough may have a “U” shape cross section), the UVC light assembly maybe mounted above (and optionally enclosing) the trough. Alternatively,when the germicidal includes ozone, the trough is likely to be entirelyenclosed (except for the food entry and exit openings at its ends)thereby substantially preventing ozone from escaping the trough.Attached to the flights may be a plurality of tumblers as describedhereinabove for tumbling the individual food products over or under thetumblers. Thus, such tumblers may continuously lift the food productabove the auger shaft so that the lifted food product tumbles down,e.g., an opposite side of the auger shaft (or an opposite side of atumbler) so that it is expected that substantially all surfaces of thefoodstuff will be exposed to a sterilizing or decontaminating dosage ofthe germicidal.

[0045] Thus, in at least some embodiments of the surface sterilizer, itis an aspect that above (or more generally, adjacent to) the auger theremay be one or more ultraviolet light assemblies mounted (e.g., in afixed position) for providing an effective sterilizing dosage of agermicidal to the foodstuff traversing the screw conveyor. Inparticular, the ultraviolet light assemblies may be provided, e.g., in alid covering at least a portion of the open portion of the trough. Thus,for a germicidal that at least includes UVC, the lifting and tumblingaction of the foodstuff within the screw conveyor causes substantiallyall surfaces of the food product to be exposed to the ultraviolet lightgenerated by the light assemblies.

[0046] Additionally such a screw conveyor may be inclined so that thefoodstuff therein moves with or alternatively against gravity.

[0047] Accordingly, in additional to the type and intensity of thegermicidal utilized by the surface sterilizer, one or more of thefollowing parameters may be important in various embodiments of theinvention for determining and/or controlling the food product exposureto the germicidal: the angle of inclination of the rotational component,the rotational direction of the rotational component, the speed ofrotation, the vertical distance that the food product is lifted by thetumblers, the tumbler design, any helical ribbon (e.g., provided withina rotating drum), and/or controlling the amount of food product beingsterilized within the surface sterilizer at any given time.Additionally, note that when the germicidal is provided by ultra violetlight assemblies (e.g., having UV emitters therein), the total wattageof the light assemblies, operating temperature of the light assemblies,and the distance of the light assembly to the foodstuff beingsterilized, combined with the time in which the foodstuff is exposed tothe generated ultraviolet light determines the resulting dosage ofultraviolet light in microwatts-seconds per square centimeter as oneskilled in the art will understand.

[0048] Moreover, when the rotational component includes an auger, theauger pitch (i.e., the distance between auger flights), the augerrotational speed, and the length of the trough exposed to the germicidalmay impact the time of food product exposure to the germicidal.

[0049] In one aspect of the invention, the diameter and the length ofthe rotational component may be engineered to accommodate the requiredthroughput for a specific food product being processed.

[0050] In another aspect of the invention, the rotational component maybe substantially vertical. Moreover, when a helical ribbon or an augeris utilized, such a rotational component may provide a downwardlyspiraling path for the food product for exposing it to the germicidal,wherein, e.g., there are tumblers for the food product to tumble over(or under) while spiraling downward.

[0051] In another aspect of the invention, frozen foodstuff processedaccording to an embodiment of the present invention can be processed insuch a manner so as to not substantially increase the temperature orthaw the frozen foodstuff. In particular, air of an appropriatetemperature may be circulated through the rotational component toprevent the warming of frozen foodstuffs being thereby contacted.Moreover, embodiments of the surface sterilizer may be insulated toreduce food product temperature change by conduction to the ambientatmosphere through the exterior of the food product containing portionof the surface sterilizer (e.g., the drum or trough).

[0052] In some embodiments, the surface sterilizer may be jacketed toallow circulation of chilled water, chilled glycol solutions, hot water,steam, etc., for the purpose of maintaining or increasing/decreasing thetemperature of the product being surface sterilized.

[0053] In some embodiments of the surface sterilizer having, e.g., ascrew conveyor assembly, there is an infeed hopper wherein the surfacesterilizer outputs a consistent flow of food product from a bulk supplyof foodstuff to the infeed hopper. In some food processing applications,the infeed hopper and/or equipment for receiving foodstuff from thesurface sterilizer may be equipped with components so that the foodstuffcan be batch processed, e.g., the foodstuff can be accumulated andmetered (e.g., in equal portions) into the subsequent food processingsteps (e.g., packaging).

[0054] As a further embodiment of the present invention, the transportof the surface sterilizer (e.g., an auger trough, a drum or an innerdrum) may be perforated for the separation of smaller than desiredparticulates from food particulates of a desired size, and/or for theseparation of particulate food product from a liquid, while surfacesterilizing the particulate food product.

[0055] For embodiments of the invention having a rotating drum and thatutilize UVC for foodstuff sterilization, the transport of the surfacesterilizer (e.g., a rotating drum or an auger trough) may have inlet anddischarge UVC attenuating baffles or radiation baffle structure tothereby create a substantially enclosed housing for at least one of: (a)containing substantially all of the ultraviolet radiation within thevolume of the transport, and (b) altering the ultraviolet radiation thatmay escape from the transport so that the escaping radiation is nolonger considered a threat to humans; and therefore, meeting OSHA andrelated safety requirements for personnel working in the vicinity ofthis embodiment of the invention. In some preferred embodiments, thebaffles or baffle structure is made of translucent materials that allowvisibility of the food product inside the transport. Moreover, when thesurface sterilizer includes an auger trough, the lid (that encloses theUVC light assemblies above or adjacent to the trough) is constructed ofa UVC attenuating material, to create a substantially enclosed volumefor human harmful radiation.

[0056] Additional aspects and features that may be related to thepresent invention may be found in one or more of the following U.S.patent applications: U.S. Provisional Patent Application Serial No.60/393,792 filed Jul. 3, 2002; U.S. Provisional Patent ApplicationSerial No. 60/393,363 filed Jul. 3, 2002 (directed to an apparatus andmethod for sterilizing a food product within a food processing screwconveyor); and U.S. Provisional Patent Application titled “TravelingSurface Sterilization Method And Apparatus” filed Feb. 24, 2003 havingattorney docket number 4878-4PROV, each of these patent applications arefully incorporated herein by reference.

[0057] Other features and benefits of the present invention will becomeevident from the accompanying drawings and Detailed Descriptionhereinbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

[0058]FIGS. 1A and 1B is a perspective view of one embodiment of thesurface sterilizer 181 of the present invention, wherein the surfacesterilizer 181 includes a rotatable drum 111 as the rotationalcomponent, and the drum 111 is floor-mounted and irradiates foodstuffwith ultraviolet energy as the germicidal.

[0059]FIG. 2 is a perspective view of an embodiment of the surfacesterilizer 181 to that of FIG. 1A, wherein: (i) the food productreceiving end 1291 is shown receiving a food product 115 from a conveyor116, and (ii) a portion of the drum 111 is cut away to expose the drum'sinterior.

[0060]FIG. 3 is a cross sectional view of the surface sterilizer 181 ofthe embodiment of FIG. 1 (and also FIG. 2), wherein the view is of thecross section of the surface sterilizer that is coincident with thesectioning plane associated with the arrow P3. Note that the arrow P3points to the side of the sectioning plane from which a viewer views thecross section.

[0061] FIGS. 4A-4I shows alternative cross sectional embodiments of thetumblers 191 with their preferred direction(s) of rotation.

[0062]FIG. 5 shows an exploded view of an embodiment of the UV lightassembly 145 also shown in FIGS. 1 and 2.

[0063]FIG. 6 shows a more detailed view of the watertight electricalconnection between the UVC lights 161 and the UV light assembly 145.

[0064]FIG. 7 is a side view of the ceiling hung surface sterilizer 181,wherein the surface sterilizer 181 includes a rotatable drum 111 as therotational component for irradiating foodstuff with ultraviolet energy.

[0065]FIGS. 8A and 8B are, respectively, a side and end view of anotherembodiment of the surface sterilizer 181, wherein the surface sterilizer181 includes a rotatable drum 111 as the rotational component, andwherein the drum 111 has a square interior contour and irradiatesfoodstuff with ultraviolet energy.

[0066]FIG. 9 shows a partial cross sectional view of an embodiment ofthe rotational component wherein this component is a drum 111 having ahelical ribbon 1221 therein for advancing a food product between ribbonflights.

[0067]FIGS. 10A through 10D show some alternative cross sectional viewsof embodiments for the UVC light reflector 151 shapes that can be usedwith one or more UVC bulbs or lamps 161 in the rotating drum 111 orscrew conveyor embodiments (e.g., FIGS. 14 and 16) of the surfacesterilizer 181.

[0068]FIG. 11 is a detail view of an alternative embodiment of the UVCemitter coupling having a water tight slip tube 1281.

[0069]FIG. 12 is a block diagram showing the controller 1400 and boththe high level components therein for controlling the surface sterilizer181, and various high level components with which the controller 1400communicates.

[0070]FIG. 13 is a flowchart of the high level steps performed by thecontroller 1400 during food product sterilization.

[0071]FIG. 14 is a isometric view of an apparatus according to thepresent invention for irradiating foodstuff with ultraviolet energy,wherein a screw auger assembly 1608 is used to both transport and tumblethe food product 115.

[0072] FIGS. 15A-15D show various alternative cross sectional end viewembodiments of the screw conveyor sterilizer 1600 showing variouslifting tumbler 1620 configurations.

[0073]FIG. 16 is a side exterior view of a floor mounted embodiment ofthe screw conveyor sterilizer 1600 operatively associated with an infeedhopper 16 according to the present invention for irradiating foodstuffwith ultraviolet energy.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0074] The invention will now be more fully described with reference tothe FIGS. 1 through 16.

[0075]FIGS. 1 through 3 are illustrative of embodiments of the surfacesterilizer 181, wherein a rotating drum 111 is used. In particular, FIG.1A is a perspective exterior view of the surface sterilizer 181 showingthe food product output end of the surface sterilizer 181, wherein thedrum 111 is used for rotatably sterilizing food products 115 providedtherein. Additionally, FIG. 2 is a cut away perspective view of the foodproduct receiving end of a substantially identical embodiment of thesurface sterilizer 181 to that of FIG. 1A, wherein there is a cut awayshowing the interior of the drum 111. The primary difference between theembodiments of FIGS. 1A and 2 is that the food product receiving end ofthe surface sterilizer 181 of FIG. 1A is attached to an opening in awall 1101 of a food processing facility for receiving food products 115through the opening, whereas in FIG. 2 the surface sterilizer receivesthe food products 115 from a conveyor 116, and there is a UV attenuatingenclosure surrounding the drum 111 food product receiving end. FIG. 3 isa cross sectional end view of the surface sterilizer 181 of FIG. 1A (andalso FIG. 2), wherein cross section of FIG. 3 is associated with theview arrow labeled “P3” in FIG. 1A (as is further described in the BriefDescription of Drawings section above). Additionally, note that thegermicidal emitting component includes one or more UVC light assemblies145, each including UVC lamps or emitters 161 (FIG. 5) and a reflector151 used for irradiating foodstuff 115 which are conveyed through thedrum 111.

[0076] The drum 111 may be substantially cylindrical in shape and theinterior of the drum may be substantially UVC light reflective, e.g.,the interior of the drum may be a polished surface that reflects UVlight such as: polished stainless steel, polished aluminum, polishedzinc, or polished coatings such as magnesium carbonate, nickel orchromium. The drum 111 may be manufactured with continuous welds toprevent the creation of crevices in which food particulates and bacteriaor other micro-organisms could harbor, and thus prevent the drum frombeing easily sanitized. In one embodiment, for products 115 which aresensitive to temperature change, the drum 111 may be insulated with nonmoisture-absorbing insulation material which is sheeted over withstainless steel on the drum exterior thereby enclosing the insulation.The insulation may be selected to minimize conductive heat transfer tothe exterior of the drum 111, e.g., the following insulations may beused: polyurethane, polystyrene, fiberglass, calcium silicate. Thus, forfrozen food products 115 in unconditioned ambient environments, such aninsulated drum 111 may prevent the sweating of the exterior of the drumcaused by condensation of moisture from the unconditioned ambientenvironment. In another embodiment of the drum, it may be manufacturedof sheet metal material with perforations or holes, which serve toseparate solid materials and liquid materials, or to allow materials ofa lesser particle size than desired to be separated from the larger foodproduct 115 pieces (e.g., such smaller sized particles can fall throughthe drum holes). Such a perforated drum 111 may be particularly usefulin surface sterilization of raw whole potatoes where surface dirt can beremoved by allowing the dirt to pass through the perforations in thedrum. Additionally, such a perforated drum 111 may be useful for surfacesterilizing vegetable products that are conveyed in water, wherein theperforations can be used to separate the water from the vegetableproduct by allowing the water to pass through the perforations in thedrum.

[0077] Referring to the embodiments of FIGS. 1-3, the drum 111 is shownwith food product tumblers 191 on the inside circumference of the drumfor lifting and tumbling the food product 115 within the drum. Thetumblers 191 protrude from the inside circumference of the drum 111,wherein each tumbler may protude at an angle from 15 degrees to 90degrees (see FIGS. 4A-4I for tumbler profiles) to the tangential line ofthe drum interior where tumbler is attached. The tumblers 191 may extentinwardly from the drum's interior surface from 1 inch to 12 inches. Thetumblers 191 may have a length that is parallel to the drum rotationalaxis 1341. In additional embodiments, the tumblers 191 may be at anangle to the drum rotational axis in which the product tumblers 191 mayassist with the movement of the food product 115 through the drum. Theangle (more generally configuration or shape) and distance of protrusionof the tumblers 191 substantially determine both the amount of foodproduct 115 lifted by each tumbler 191, and the point at which the foodproduct tumbles downward off of the tumbler as the drum rotates. Thegentile handling of fragile food products 115 which are sensitive tobreakage requires a tumbler profile angle that assures the food productis always tumbling as compared to being lifted and allowed to free fallfrom a tumbler to the bottom of the rotating drum.

[0078] The drum 111 has substantially open ends 1291 and 1311 for,respectively, receiving and outputting food products 115. In particular,the receiving drum end 1291 receives a food product 115 from a foodproduct infeed device 1101 associated therewith for providing a foodproduct 115 to the drum 111. The food product 115 is deposited into thedrum 111 by the product infeed device 1101 at the product receiving end1291 at a height above the lowest inside surface of the drum whereinthis height is also greater than the expected depth of the food productin the drum. The infeed device 1101 may be, e.g., a conveyor 116 (FIG.2) such as a shaker, belt or auger conveyor, a foodstuff storage bin, oran entire food processing facility prior to packaging (as shown in FIG.1A where the receiving end 1291 is attached to a wall opening in achicken wing production plant for receiving processed chicken wingsimmediately prior to packaging). Note that, at least at the food productreceiving end 1291 of the drum 111, the drum opening 1104 for receivingfood products 115 may be restricted so as to prevent the input foodproduct from spilling out of the receiving end of the drum 111. Inparticular, as described further below, the receiving end 1291 of thedrum 111 may have an reinforcing support 1301, e.g., in the shape of anannular ring, for: (i) maintaining the drum's shape when, e.g., loadedwith foodstuff 115, and (ii) narrowing the receiving drum opening 1104.Moreover, the distance from the outer circumference of the drum 111 tothe inner circumference of this annular ring 1301 may vary dependingupon: (a) the food products to be provided to the drum 111, and (b) theexpected depth of the food products in the drum during operation.Preferably, this distance is effective for preventing the food productsfrom spilling out of the receiving end 1291 of the drum, and the infeedring 1301 may be approximately four inches to eight inches smaller indiameter than the interior diameter of the drum 111 for keeping thefoodstuff 115 from falling out of the drum end 1291. Further, note thatthe support 1301 may also have an outside diameter that is larger thanthe diameter of the drum 111, and accordingly such a larger diameterprovides additional reinforcement for maintaining drum alignment inrelation to the rotational axis 1341 of the drum. In one embodiment, thereinforcing support 1301 may be detachable so that, e.g., drum rings1301 having openings of different exterior and/or interior diameters maybe attached to the drum end 1291. Moreover, in another embodiment, afirst drum ring 1301 may be fixedly attached to the drum end 1291, andas needed (depending on, e.g., the expected depth of the food productwithin the drum 111), additional drum rings may be attached to (ordetached from) the first drum ring to thereby decrease (or increase) thediameter of the opening 1104.

[0079] The discharge drum end 1311 outputs the sterilized food product115 to a food product discharge subsystem 1121 adjacent thereto forreceiving the food product 115 as it exits the drum 111. The dischargesubsystem 1121 may include, e.g., a conveyor, a food bin, a foodweighing station, or a screw type auger. Moreover, the dischargesubsystem 1121 may include a food slide or chute 1123 operably attachedto a frame 141 so that the food product 115 within the drum 111 exitsthe drum and contacts the discharge device without bruising the foodproduct. Optionally, the discharge subsystem 1121 may include anelectromechanical gate that periodically opens to allow at least aportion of the food product 115 within the drum 111 to exit. In typicalembodiments of the surface sterilizer 181, the retention time forsterilization of food product 115 in the drum 111 in the range of 2seconds to 60 seconds depending on such parameters as the diameter andlength of the drum 111, the configuration of the drum interior (e.g.,the configuration of the tumblers 191), the inclination of the drumrotational axis 1341, the amount of food product in the drum 111, thedesired food product exposure to the germicidal, the shape and textureof the food product being sterilized, the UVC irradiance generated bythe UVC light assemblies 145.

[0080] The drum end 1311 also has a reinforcing support 1321, tomaintain the drum's shape when, e.g., loaded with foodstuff 115. Each ofthe drum end reinforcing supports 1301 and 1321 may be an annular metalring whose centers are substantially in line with the rotational axis1341 of the drum 111. The discharge reinforcing support ring 1321, inaddition to acting as a reinforcement to keep the drum 111 round, has acentral circular opening with an inside diameter that may be onlyslightly larger than the outside diameter of the drum 111 so that it canbe tightly secured to the outside of the drum 111. Moreover, dependingon the drum 111 length

, embodiments of the drum 111 may have one or more additional supportrings similar to support ring 1321 provided along the drum's length.Additionally, there may be a plurality of beams or rods that extendbetween and attached to the rings 1301, 1321 and any intermediatereinforcing rings for providing additional structural support to thedrum 111.

[0081] In some embodiments, the support 1321 may be attached to thecircular drum edge 1345 and thereby act as a drip ring for wet foodstuff115, or for condensation that forms on the exterior of an un-insulateddrum operating with refrigerated or frozen foodstuff. Accordingly, sucha drip ring can be used for accumulating water droplets so that suchwaste liquid can fall free from the desired foodstuff 115 thus keepingthe waste liquid from reentering the sterilized foodstuff or beingretained with the sterilized foodstuff exiting the drum 111.

[0082] Regarding the structural frame 141, the drum 111 is supportedfrom the floor by this frame which may be made of, e.g., of corrosionresistant materials such as stainless steel angles or tubes, andengineered for adequate structural strength to support the imposed loadswith a minimum of deflection. Such frames 141 may be manufactured withcontinuous welds to (a) prevent the creation of crevices in which foodparticulates and bacteria could harbor, and (b) cause the frames to beeasily sanitized. The frame 141 includes a rectangular cage 1346surrounding the drum 111. On the lower horizontal beams 1347 of theframe 141 there is support structures for:

[0083] (i) a drive mechanism 171 (described hereinbelow) for rotatingthe drum 111,

[0084] (ii) drum support wheels 121 (described further hereinbelow),

[0085] (iii) a plurality of drum safety alignment mechanisms 1348 whichin FIGS. 1-3 are elbow-like projections that angle upwardly toward thedrum 111 from the beams 1347 on each side of the drum; such mechanisms1348 facilitate drum 111 alignment within the cage 1346 by, e.g., havingrollers (not shown) on their free ends for rolling along the exterior ofthe drum 111 as it rotates so that any undesired forces that mightmisalign the drum from its operational position (e.g., from rotatingabout the axis 1341) within the cage 1346 can be dampened.Alternatively, instead of having rollers at their free ends, thealignment mechanisms 1348 may have a low friction pad or plug at theirfree ends that are spaced apart or offset from the drum exterior surfaceby a relatively small amount (e.g., 0.25 to 0.5 inches) when the drum isproperly aligned about the rotational axis 1341. Thus, if the drum 111deviates sufficiently from rotating about the axis 1314, the exterior ofthe drum will contact one or more of the safety alignment mechanisms1348 for thereby at least inhibiting any further drum alignmentdeviations. Note that such pads or plugs are well known in the art, andmay be made from such materials as Teflon or an ultra-high molecularweight polymer (UHMW). Furthermore, the offset free ends of thealignment mechanisms may have a contour that parallels the exterior ofthe drum 111. In other embodiments, (depending on the food processingenvironment) the offset free ends may be made of other materials suchas: metal, or a material that does not induce sparking when it comes incontact with the exterior drum surface.

[0086] Adjacent the upper corners of the cage 1346 nearest the foodproduct receiving end 1291, the frame 141 also supports one or morestabilization roller assemblies 1349 which limits the position of thedrum 111 to a predetermined extent of the axis 1341; i.e., the rollerassemblies 1349 prevent the rotating drum from traveling along the axis1341 so that it would travel outside the cage 1346 or hit the cageduring rotation. In the present embodiments of FIGS. 1-3, each of thestabilization roller assemblies 1349 includes a pair of rollers 1350,wherein each of the rollers 1350 rotates about its own shaft (not shown)that is provided within a housing 1352 which is secured to the foodproduct receiving end upper corners of the cage 1346. For each pair ofrollers 1350, one roller rolls along a recessed track 1354 on the sideof the support ring 1301 facing the exterior surface of the drumextending toward the food product output end 1311, while the otherroller of the pair rolls along a corresponding track (not shown) on theopposite side of the support ring 1301. The stabilization rollerassemblies 1349 may be located in any of the upper and/or lower cornersof the cage 1346. Additionally, such stabilization roller assemblies maybe located so that the rollers 1350 roll on a track about anothersupport ring such as the support ring 1321.

[0087] There are one or more UVC light assemblies 145 located inside thedrum 111, these assemblies being supported by a light supportsubassembly 1351 of the structural frame 141. In one embodiment, thelight support subassembly 1351 supports a light assembly mountingstructure 1353, wherein the mounting structure supports' the one or moreUV light assemblies 145 within the drum 111. Note that in oneembodiment, the mounting structure 1353 includes one or more ramps 1355and jointed arms 1357 suspended from the ramps, wherein the lightassemblies 145 hang from the lower ends of the arms 1357 and the upperends of the arms have wheels 1359 attached thereto for rolling on theramps 1355. Moreover, since the ramps 1355 extend beyond at least oneend 1291 and 1311 of the drum 111 (in FIG. 1A, the end 1311), the lightassemblies 145 can be easily removed from the interior of the drum 111for cleaning or other maintenance (e.g., UV emitter 161 replacements).

[0088] As mentioned above, the structural support 141 also providessupport for wheels 121 for supporting the weight of drum 111 such thatthe drum 111 can rotate on these wheels. In one embodiment, there are atleast three such wheels 121 (e.g., two on one side of the drum and oneon the other side of the drum), and in some embodiments, at least foursuch wheels (e.g., FIGS. 1 and 2 show four wheel embodiments wherein afirst pair of wheels is shown, and the other pair of wheels 121 supportthe drum on the hidden drum side).

[0089] In the embodiment of FIGS. 1A and 2, the inclination angle of thedrum 111 is adjusted with an adjustment screw 131 (not shown in thesefigures, but a corresponding screw is shown in FIG. 7 describedhereinbelow) which elevates or lowers the receiving end 1291 of the drum111 while the discharge end 1311 of the drum 111 is fixed and situatedto pivot on a point supported by the drum support frame 141. Referringto FIG. 1, inclination angle adjustment of the surface sterilizer 181 isaccomplished by changing the vertical position of the drum rotationaldrive wheel 121 nearest the receiving end 1291 while the discharge end1311 is in a fixed position and allowed to pivot. Accordingly, suchheight adjustments change the inclination of the drum rotational axis1341, e.g., away from the horizontal, and alter the retention time ofthe food product 115 in the drum being exposed to the UVC light.Moreover, it is an aspect of the invention that such drum inclinationadjustments can be made while the present invention is fully assembledand operable. In one embodiment, the range of angles through which thedrum 111 can be inclined is approximately 0 degrees to 20 degrees.However, it is within the scope of the present invention for greater orlesser ranges to be operably available, and in one extreme case, theinclination of the drum 111 may approach a vertical orientation.

[0090] In another embodiment, the inclination angle of the drum 111 maybe adjusted with drum inclination adjustment screws 131, wherein theremay be a corresponding screw 131 for each of the wheels 121 nearest thedrum end 1291. In particular, each of the screws 131 may be operablyconnected to a corresponding one of the wheels 121 so that the screw canbe used to adjust the height of its corresponding wheel and thus alsoadjust the height of the drum inlet 1291.

[0091] In another embodiment, one or more of the screws 131 may bethreaded through a cross member (not shown) of the frame 141, whereinthe cross member extends underneath the drum 111. An upper most end ofthe screws contact a wheel support member (not shown) also extendingunderneath the drum 111, wherein the wheel support member supports thewheels 121 nearest to the drum end 1291, and wherein the wheel supportmember is vertically moveable above the cross member. In particular, thewheel support member may rest on the uppermost end(s) of the one or morescrews 131 and moves up or down in height with a height change of theuppermost end(s) of the screws. Thus, depending on how the one or morescrews 131 are rotated, the height of the wheel support member (and thewheels 121 attached thereto) is adjusted up or down. One of ordinaryskill in the art can readily appreciate that there are numerous ways ofadjusting the inclination of the drum 111 in addition to the mechanicalembodiments described here. In particular, such inclination adjustmentscould be made by hydraulics, pneumatics and/or jacks of various types.Additionally, note that such inclination adjustments could be made byadjusting the relative heights of the legs 141 a of the frame 141 as oneof ordinary skill in the art will understand. Further, note that suchadjustments can be placed at the drum end 1311 instead of, or, incombination with, drum inclination adjustments at the drum end 1291.Moreover, the inclination of the drum 111 may be electronicallycontrolled, and the drum inclination may be altered while the drum isrotating with food product 115 being sterilized therein.

[0092] The rotational motion of the drum 111 is created by therotational motion generated by a drive mechanism 171 (FIG. 1B), whichincludes, e.g., an electric, hydraulic, or pneumatic motor 173, plus anactuator (not shown). The actuator communicates with a controller 1400(FIG. 12 and described in more detail hereinbelow) for, e.g., settingthe rotational rate output by the motor 173. The rotational motionoutput by the motor 173 rotationally drives a pulley 1201. In oneembodiment (FIGS. 1A and 1B), there is a belt 1141 that securely fitsaround the circumference of the drum 111 and additionally around thepulley 1201 such that the rotational motion of the pulley causes thebelt 1141 to travel about the drum thereby rotating the drum. Note thatthere are numerous other techniques for rotating the drum 111. Inparticular, the drive mechanism 171 may be used to rotate one or more ofthe wheels 121 (either through a gear box or by a direct driveconfiguration).

[0093] Additionally, note that the present invention may also include abraking assembly (not shown) for stopping the rotation of the drum 111,e.g., in case of an emergency. Such a braking assembly may be activatedvia an emergency button 1404 prominently located on or near the surfacesterilizer 181 (e.g., in FIG. 1 on the control box 1406 which is thejunction box for substantially all electrical power to be used by thesurface sterilizer 181). The braking assembly may include a brakingmechanism substantially similar to a conventional disk brake such thatthe disk brake uses the portions of one or more of the support rings1301 and 1321 that extend outwardly from the exterior surface of thedrum 111. Alternately, a brake motor may be applied for stopping therotation of the drum, which involves a disc friction type brake thatactuates when such a brake motor is de-energized.

[0094] In some embodiments of the surface sterilizer 181 there can beone or more mechanisms to provide an even flow of food product 115 tothe rotating drum 111 and/or maintaining within a desired range anamount of food product 115 within the drum. In particular, there may beone or more food input sensors for sensing when the rate of food product115 entering the drum 111 should be increased or decreased by, e.g.,slowing or increasing the rate at which the food product is delivered tothe drum 111. In particular, such food input sensors may provide to thecontroller 1400 signals indicative of, e.g., a weight, or a volume offood product: (i) entering the drum 111, and/or (ii) at a predeterminedlocation upstream in the food product processing flow toward the drum.The controller 1400 can then use this information to determine drum 111utilization (e.g., the amount of food product 115 being sterilized inthe drum, and/or the degree of sterilization being performed). Furtherdescription of the controller 1400 and its data inputs and outputs areprovided below.

[0095] In some embodiments, food input sensor(s) may be used to detectfood product falling accidentally out of the drum 111 and/or fallinginto the drum 111 at the receiving drum end 1291. Each such sensor maybe an optical or infrared sensor (not shown) for detecting food productfalling through the air. Alternatively, such a sensor may include aweight sensitive platform (not shown) that registers abrupt changes inweight greater than a predetermined amount. Such a weight sensitivesensor may be placed immediately adjacent to and below the food inletopening 1104 of the drum end 1291.

[0096] Moreover, one or more drum capacity sensors may be provided inthe drum 111 or adjacent to the drum for determining whether there istoo much food product 115 in the drum, or whether the drum and thegermicidal emitters have the capacity for sterilizing additional foodproduct. For example, within the drum 111 there may be one or moredownwardly directed food product depth probes 1408 (e.g., FIG. 2 andFIG. 3), wherein each such probe can easily detect contact with the foodproduct 115 in the drum 111. In particular, the probes 1408 may detectsuch a food product 115 contact by sensing a force from the contact, orby sensing a positional deflection of the probe (e.g., being deflectedthrough a predetermined angle more than a specified frequency, and/orfor a predetermined time period) via contact with the in-drum foodproduct. With one such in-drum probe 1408 (or a plurality of probesprovided along the length

at the same depth in the drum 111 interior), product overload can besensed, and perhaps a damming or blockage within the drum. However, byproviding a group of a plurality of such probes 1408 wherein the probesof the group are at a plurality of different depths within the drum 111(and optionally, providing such a group of probes at various locationsalong the length

of the drum), a depth of the in drum food product 115 can be estimated.For example, if there are three such probes 1408, relatively near oneanother, wherein each of the probes extend to a different depth in thedrum 111, then at least four food product 115 depth classifications maybe estimated for the portion of the drum interior where the probesdownwardly extend; i.e., a depth classification corresponding to none ofthe probes 1408 swinging, a depth classification corresponding to onlythe lowest of the probes swinging, a depth classification correspondingto at least the second to the lowest of the probes swinging, and a depthclassification corresponding to at least the highest of the probesswinging. Accordingly, a “food product” overload condition is likely toexist when at least the highest of the probes 1408 is being sufficientlycontacted by the in-drum food product 115, and in such a circumstance,signals may be provided to the controller 1400 so that the controllercan initiate one or more of the following: (a) slow/stop the rate offood product being provided to the drum 111, and/or (b) alert anoperator of the condition. Additionally, if the lowest probe 1408 doesnot detect contact by the in-drum food product 115, this may beindicative of either too little food product within the drum 111, or adamming/blockage within the drum. Thus, such in-drum probes 1408 can beused to detect anomalous conditions within the drum 111 such as dammingor bunching (or some other blockage) of the food product 115 within thedrum. For instance, if a food product 115 overload condition is detectedby the probes 1408 in one portion of the drum interior, and downstreamwithin the drum 111, a reduced amount of food product is detected, thena blockage may have occurred within the drum 111.

[0097] Some other sensors that may be used with various embodiments ofthe surface sterilizer 181 are:

[0098] (a) a drum weight sensor for weighing the drum 111, and therebyallowing the controller 1400 to determine the weight of the food product115 within the drum 111;

[0099] (b) a food product weighing sensor for weighing the food productexiting and/or entering the drum 111;

[0100] (c) a temperature sensor for measuring a temperature within thedrum;

[0101] (d) one or more optical or infrared sensors for sensing one ormore light beams traversing the length

of the interior of the drum at one or more depths within the drum 111for performing substantially the same functions as the probes 1408described hereinabove;

[0102] (e) one or more non-contact ultrasonic distance sensors withanalog outputs for sensing product depths within the drum 111 at one ormore locations for performing substantially the same functions as theprobes 1408 described hereinabove;

[0103] (f) one or more germicidal in-drum concentration sensors fordetecting an abnormal concentration of the germicidal; e.g., when thegermicidal is UV, the amount of UV light contacting the food product maybe undesirably reduced due to the UV light assemblies 145 being cloudedor coated with food product debris. Such sensors may be spaced apartfrom the one or more UV light assemblies 145, and when the sensorsdetect a low enough level of UV light, then it may be assumed thatapproximately no more than twice the amount of UV light detected isbeing utilized for surface sterilization of the in-drum food product115.

[0104] Since the ends 1291 and 1311 of the drum 111 may be (andtypically are) substantially open, there is the possibility (when UVC isused as the germicidal) of the UVC light escaping from the interior ofthe drum and damaging the eyes and/or the skin of personnel in proximityto the surface sterilizer 181. Accordingly, at least in areas where anoperator and/or other personnel may be subject to such radiation, thepresent invention includes components so that the UVC is substantiallyprevented from contacting personnel about the drum 111. In particular,the UVC light may be attenuated on the infeed (i.e., receiving) end 1291of the drum 111, and/or also on the discharge end 1311 by correspondingadjacent UVC attenuating baffles 1191 (shown in FIG. 1A as only on thedischarge end 1311 and shown in FIG. 2 on the food product receiving end1291). Such baffles 1191 may be made of, e.g., (i) a rigid (andpreferably substantially clear) UVC attenuating plastic (e.g., FIG. 1A),or (ii) a flexible (and preferably substantially clear) UVC attenuatingplastic (e.g., FIG. 7 described hereinbelow) as is typically used aswelding curtains for protection of eyes and skin of personnel in thearea of the welding activity, or (iii) a more rigid and opaque materialsuch as metal. In one embodiment, the baffles 1191 may be at leastpartially UVC reflective on their sides facing the interior of the drum111 so that the escaping UVC light is reflected back into the drum 111.Note that when a perforated drum 111 is used, the baffles 1191 may beapplied around the entire drum for the protection of eyes and skin ofpersonnel in the area from ultraviolet rays. In one such embodiment, theUVC attenuating baffles 1191 shown in FIG. 1A may be enlarged to includethe entire drum 111.

[0105]FIG. 3 is a sectional end view of the embodiments of FIGS. 1 and2. FIG. 3 shows one embodiment of the profile of the tumblers 191 on theinside circumference of the drum 111. Accordingly, the tumblers 191 liftand tumble the food product 115 in the drum 111 thereby exposingsubstantially all surfaces of the food product to the UVC lightgenerated by the UVC lamp(s) or emitters 161 (FIG. 5) within the lightassemblies 145. Note that it is an aspect of the present invention forthe light assemblies 145 and/or the UVC lamp(s) 161 and/or theirreflector(s) 151 to be tilted or obliquely oriented so that most of theUVC light is directed toward those portions of the interior of the drum111 where the food product 115 is prone to collect while being rotated.In particular, the light assemblies 145 may be oriented so that theirgenerated UVC light is substantially directed to an angular range (ofthe drum's interior) of approximately 90 to 120 degrees about the drumrotation of axis 1341, wherein this range generally extends (relative tothe drum interior's lowest portion): (i) from 5 to 15 degrees againstthe rotation of the drum, and (ii) to an angle of 80 to 115 degrees inthe direction of drum rotation.

[0106] FIGS. 4A-4I show various alternative cross sectional or profileviews of the tumblers 191 which may be utilized with various drum andauger screw embodiments of the surface sterilizer 181. Note that arrow1194 shows the preferred direction(s) of drum 111 rotation for each ofthese alternative tumbler 191 configurations. In various embodiments,the tumblers 191 may be one of: (a) parallel to the rotational axis 1341of the drum 111, i.e., the tumbler has a substantially uniform crosssection (e.g., as shown in FIGS. 1 and/or 4A-4I) along the tumblerlength, and this length is substantially parallel to the axis 1341, or(b) angled to the rotational axis 1341 of the drum to assist in themovement of the food product 115 through the drum 111 (or in someembodiments, oppose movement of the food product through the drum). Notethat it is an aspect of the invention that tumblers 191 having differentprofiles may be interchangeably attached to the interior surface of thedrum 111. In particular, the drum interior surface may include recessesfor attaching or locking tumblers 191 of various heights and/or anglesto the drum interior surface. Thus, a single drum 111 may appropriatelytumble relatively small food product 115 items such as nuts as well aslarger and/or more irregularly shaped food product items such ascauliflower. Additionally, as shown in FIG. 9, the tumblers 191 may becombined with a food product advancing helical ribbon 1221 inside thedrum 111, wherein this ribbon may assist in the movement of the foodproduct 115 through the drum.

[0107]FIG. 5 shows an exploded view of the UV light assembly 145providing an illustration of the components included in the UV lightassembly. However, note that for clarity, the number of at least some ofthe components is not represented in FIG. 5. The UV light assembly 145includes a longitudinal frame member 155 (also denoted a baffle) whichis the primary component to which the other structural components areattached. Additionally, the baffle 155 provides the mountings forvarious electrical components of the light assembly 145. In particular,the baffle 155 includes mounts for a plurality of electrical ballasts159 for providing the desired voltage to activate the UV emitters 161,and for stabilizing the current to the UV emitters. In one embodiment,the power supplies 159 for the light assembly 145 include Steril-Airepart number 10000125, SE/SEN 16-24 Power Supply, 115 Volt asmanufactured by Steril-Aire, 11100 E. Artesia Blvd., Cerritos, Calif.90703. However, note that power supplies 159 are selected to becompatible with the UVC emitters 161 and operating voltage of theparticular embodiment of the invention. In one embodiment, twelve suchballasts 159 may be mounted on the baffle 155.

[0108] At each end of the baffle 155 there is a corresponding one of theend supports 163 a and 163 b attached thereto by lug attachments 164(only one such lug attachment is shown in FIG. 5; however, there are atleast two such attachments for attaching each of the end supports to thebaffle 155). Each of the end supports 163 a and 163 b includes arespective plurality of UV emitter 161 holding bores 167 a and 167 b,wherein each of the bores secures an end of one of the emitters 161 tothe light assembly 145. More precisely, there is a pair of bores 167 aand 167 b for securing each of the emitters 161 to the light assembly145. Note that bores 167 b are larger than the bores 167 a since thebores 167 b secure the electrical coupling 169 (FIG. 6) to the endsupport 163 b, wherein the electrical coupling supplies a watertightelectrical connection to its emitter 161 for supplying electrical powerfrom one of the ballasts 159 to this emitter. In the present embodiment,there are twelve bores 167 a and twelve bores 167 b that aresubstantially equally spaced adjacent to and generally following thecurve of the lower edge 175 of each of the end supports 163 a and 163 b.Note that the curve of the lower edges 175 (and more importantly thecurve of the emitters 161) may correspond to a curve that is an offsetcurve from the corresponding curve of a cross section of an adjacentportion of the drum 111 interior. That is, the curve is such that eachof the emitters 161 is approximately the same distance from the nearestpoint of the interior of the drum (e.g., between tumblers 191) on whichUV light directly shines. Note, however, in another embodiment the curveof the emitters 161 may have a reduced curvature in comparison to thecurvature of the drum 111 interior. In particular, the reduced curvaturemay parallel the expected general curvature of the foodstuff surfaces inthe drum that are exposed to the UV light.

[0109] Additionally, at least the end support 163 b includes holes 176and 177, wherein electrical wiring is provided to the ballasts 159 (viahole 176) for supplying electrical power to the ballasts, and whereinelectrical wiring is provided from the ballasts 159 to the couplings 169(via hole 177) for supplying electrical power to the emitters 161.Moreover, note that the electrical power for the ballasts 159 isprovided via an electrical connector 179 which provides a watertightelectrical connection through an end cover 180 b, this end cover beingsealed tightly to the end support 163 b with gasket 182 b therebetweenfor watertightness, wherein this gasket is into a milled groove in endsupport 163 b. Further note that there is a corresponding end cover 180a for end support 163 a with a gasket 182 a set into a milled groove inend support 163 a therebetween for watertightness.

[0110] Each of the end supports 163 a and 163 b also includes a pair ofmounting attachments 184 for connecting the light assembly 145 to thejointed arms 1357 so that the light assembly 145 can be mounted asshown, e.g., in FIGS. 1-3.

[0111] Also attached to the baffle 155 is a reflector 151, wherein amajority of the reflector is curved to substantially parallel the curveof the emitters 161. The reflector 151 may be made of various materials.However, the side facing the emitters 161 should be a polished surfacethat reflects UV light such as: polished stainless steel, aluminum,zinc, or coatings such as magnesium carbonate, magnesium oxide, chromiumor nickel. Note that the reflector 151 is secured to a cover 185 thatprovides a watertight seal with at least the end supports 163 a and 163b in the following manner: The reflector 151 is set into a milled groovein each of the end supports 163 a and 163 b, wherein during the milledgroove may be filled with a flexible food grade sealant such as siliconeprior to inserting edges of the reflector 151 so that the junction ofthe end supports 163 a and 163 b and the reflector 151 is watertight.The reflector 151 is also fastened to cover 185 with screw fasteners anda gasket between the mating surfaces of reflector 151 and cover 185.Gaskets for the invention may be fabricated from materials such as:Teflon, buna N, silicone, neoprene, or another food grade rubbercompound. Moreover, there may be an optional UV translucent emittercover 199 that fits over the emitters 161 so that the emitters arebetween the reflector 151 and the emitter cover. Moreover, the emittercover 199 may be attached to the reflector 151 with screw fasteners anda gasket between the reflector and the emitter cover to create thewatertight connection, wherein the gasket material may include thegasket materials listed above. Furthermore, the emitter cover cansatisfy the watertightness criteria as described in the Terms andDefinitions section hereinabove, and additionally is scratch resistant.As an alternative (or in addition to) to the emitter cover 199, each ofthe emitters 161 are individually sleeved with a UV translucent materialthat is tightly shrink applied to the emitter tube, and which serves tocontain the quartz glass of the emitter if the emitter shatters andprevent the glass from mixing with the foodstuff 115.

[0112] The watertight aspect of the UV light assembly 145 is aparticularly important aspect of the invention. Accordingly, there aregaskets and/or seals between any two of the light assembly 145components that have a seam that is exposed to the environment exteriorto the light assembly (e.g., seal 186 between electrical connector 179and end cover 180 b). In particular, such gaskets and/or seals may becomposed of the gasket materials listed hereinabove.

[0113] Additionally, the UV light assembly 145 further includes amounting clip 200 which is attached with, e.g., screw fasteners to thebaffle 155. The mounting clip 200 is shaped to fit in a groove in theside of a wire terminal strip 202 that faces the mounting clip. The wireterminal strip 202 provides pressure wire connectors to connect thecommon power feed of the light assembly 145 to individual power feeds toeach emitter power supply 159, and additionally connect each emitterpower supply output to its associated emitter 161.

[0114] Referring now in more detail to the couplings 169, each suchcoupling includes a female threaded cap 187, a female electrical plug189, and between these two components are a coupler 192 and a pair ofO-rings 194 a and 194 b. The female electrical plug 189 is set into themale threaded coupler 192 and the void between the inside surfaces ofthe coupler 194 and the exterior side surfaces of the electrical plug189 are filled with a two part urethane sealant that reacts when mixedto form a rubber type (e.g., elastomeric) sealant which results in awatertight assembly of the coupler 192 and the electrical plug 189. Thecoupler 192 with the inserted electrical plug 189 is inserted in endsupport 163 b through a corresponding one of the bores 167 b. Each ofthe bores 167 b is machined with an internal thread to be threadablycompatible with the male threads on the bore insertion portion 196 of acoupler 192 so that the coupler can be securely threaded into the bore.Alternatively, the bore 167 b may be smooth and the coupler 192 fastenedby a threaded nut (not shown) that is threaded onto the coupler's boreinsertion portion 196 that extends through to the opposite side of thebore 167 b. However, to insure watertightness, an elastomeric O-ring 194a is snuggly fitted on the bore insertion portion 196 so that when thecoupler 192 (and its plug 189) are secured to the end support 163 b,this O-ring is compressed between the end support and the bolt-headportion 197 of the coupler 192. With the exception of the plug 189,coupler 192, and O-ring 194 a, the other components of the coupling 169are inserted onto the emitter 161 from its end that is opposite to theemitter end 198 so that when the O-ring 194 b and the threaded cap 187are positioned on the emitter, these components are in the order shownin FIG. 6, and in particular, so that the O-ring 194 a provides a firstwatertight seal between the coupler 192 and end support 163 b, and theO-ring 194 b provides an additional watertight seal between the cap 187and the emitter flange 201. More particularly, when the coupling 169 isfully assembled and connected to its emitter 161, the O-ring 194 btightly fits between the emitter flange 201 and a cylindrical portioninterior to the cap 187 (the position of this O-ring on the emitter isshown dashed in FIG. 6).

[0115] It is an important aspect of invention for embodiments thereof tobe able to operate in wide range of food processing relatedenvironments, including large variations in temperature, in humidity, inthe type and size of food products being surface sterilized, and whereinpersonnel may or may not be proximate to the surface sterilizer 181.Regarding temperature, the UVC germicidal lamps 161 should operateeffectively in food processing environments where the ambienttemperature may vary from −40 degrees Fahrenheit to +120 degreesFahrenheit. UVC emitters 161 that can operate effectively in such largetemperature varying environments are available from, e.g., Steril-Aire,Inc., 11100 E. Artesia Boulevard, Unit D, Cerritos, Calif. 90703, theseemitters known as UVC single ended sleeved emitters, Steril-Aire partnumber 21000301 (note, however, that the Steril-Aire part number isdifferent for the various emitter lengths available). The Steril-Aireemitters are low pressure mercury UVC emitters, and these emitters 161are each enclosed in a plastic material, which is shrink applied to eachemitter so that the plastic material fits tightly to the emitter and isessentially a sleeve for the emitter. Note that the plastic material ofsuch sleeves does not substantially reduce or alter the UVC lightgenerated by the emitters. However, the plastic material is ofappropriate strength to contain the glass particles in the event such anemitter 161 shatters. Note that even in embodiments of the UVC assembly145 in which the UV emitters 161 are enclosed within a housing (e.g.,provided by end covers 180 a and 180 b, cover 185, emitter cover 199,and the corresponding gaskets and/or seals), the use of such plasticcoated emitters is likely to be required in the food processing industryto further assure that glass and/or other foreign material from theemitters do not mix with the food product 115 sterilized by the surfacesterilizer 181. However, both plastic and non-plastic coated emitters161 for embodiments of the surface sterilizer 181 are available fromSteril-Aire Inc. Moreover, the Steril-Aire Inc. single ended emittersare available in lengths of 16 inches, 20 inches, 24 inches, 30 inches,36 inches, and 42 inches. Accordingly, the length(s) of the emitters 161may be selected to be compatible with the length

of the drum 111. Thus, as shown in FIGS. 1 and 2, multiple collectionsof such emitters 161 may be sequentially positioned throughout thelength

of the drum 111 so that for substantially every cross section (traverseto the length

) along the entire drum length, the cross section contacts a pluralityof the emitters. Additionally, note that the Steril-Aire single endedemitters may each provide from 50 watts to 70 watts of UVC radiation,and have (on the average) a 7,500 hour life span in operationalconditions.

[0116] UVC emitters 161 suitable for embodiments of the presentinvention are also manufactured commercially by other companies, such asAquionics, Inc. 21 Kenton Lands Road, Erlanger, Ky. 41018, and AmericanUltraviolet, 2400 W. Cape Cod Way, Santa Ana, Calif. 92703.

[0117]FIG. 7 is a side view of an alternative embodiment of a rotatingdrum embodiment of the surface sterilizer 181, wherein components havingsimilar functionality and structure to those recited above are labeledidentically. Accordingly, the present embodiment includes a drum 111with product tumblers 191 on the inside circumference of the drum andone or more light assemblies 145 having UVC lamps 161 with reflectors151 for irradiating foodstuffs 115 which are conveyed through the drum111. In the present embodiment, the drum 111 is supported from theceiling 1500 by a structural frame 141 attached to the ceiling. Thelight assemblies 145 are located inside the drum 111 and are supportedby a light assembly mounting structure 1353 and a light supportsubassembly 1351 of the structural frame 141. The rotational motion ofthe drum 111 is generated by the drive mechanism 171 which may include,e.g., an electric, hydraulic, or pneumatic motor 173 and which isoperably connected to a controller 1400 for, e.g., setting therotational rate output of the 173 motor and/or the rotational rate ofthe drum 111. The drive mechanism 171 includes drum rotational drivebelt pulleys 1201 that are supported, via drive shaft 1151, by thestructural frame 141. These pulleys 1201 provide the rotational motionto the drum 111. The drum 111 is suspended by drive belts 1141 which arerotationally driven by the pulleys 1201. The rotational motion of thedrum 111 is created by the drive mechanism 171 wherein this motion istransferred by the drive shaft 1151 to the drive pulleys 1201, then tothe belts 1141 and consequently to the drum 111. Additionally, note thatsince the drum 111 is suspended, in operation the drum 111 may have atendency to swing as the foodstuff 115 tumbles within the drum.Accordingly, drum swing retarders 1161 may be provided, wherein suchretarders contact the drum 111 during rotation to dampen or prevent sucha swinging motion. Note that the swing retarders 1161 may contact thedrum 111 with one or more wheels 1510 that are, e.g., fixedly attachedto the light support subassembly 1351 wherein each wheel 1510 rolls onthe drum exterior surface as the drum rotates. Moreover, there may alsobe stabilization roller assemblies 1349 (for simplicity, not shown inFIG. 7) which limits the position of the drum 111 to a predeterminedextent of the axis 1341; i.e., the roller assemblies 1349 prevent therotating drum from traveling along the axis 1341. Further note that theexterior of the drum 111 may include a pair of belt guides 1516 for eachof the belts 1141, wherein each belt 1141 is restrained by its pair ofbelt guides from traveling too far in any one direction along the lengthof the drum 111. In particular, each belt guide 1516 may be a ridgeraised above the exterior circular band of the drum 111 that is betweenthese ridges so that the corresponding belt 1141 travels about the drumand contacts the band to which it is restricted. Of course, as in theembodiment of FIG. 1A, other techniques for rotating the drum 111 may beused such as a mechanism for rotationally driving wheels supporting thedrum 111, wherein such wheels are supported on a portion of the frame141 that is suspended underneath the drum 111.

[0118] The inclination angle of the drum 111 of FIG. 7 may be adjustedwith the drum inclination adjustment screw 131, and a drum inclinationpivot 1181 as it is known in the art (the pivot 1181 being, e.g., apivot bar built into the frame 141 wherein the portion of the structuralframe 141 below the pivot bar is able to pivot relative to the portionof the structural frame between the ceiling 1500 and the pivot bar).Thus, the vertical position of the drum 111 receiving end 1291 remainsat a substantially fixed height while the adjustment screw 131 allowsthe height of the discharge end 1311 to vary in height. More precisely,adjustment of the screw 131 changes inclination of the drive shaft 1151and the relative heights of the pulleys 1201 (FIG. 7). It is, however,within the scope of the invention that the adjustment screw 131 can beon the receiving end 1291 of the frame 141 and the pivot 1181 then willbe on the discharge end 1311 of the frame 141. Moreover, as withpreviously described embodiments, the angle of drum 111 inclination maygenerally vary between 0 and 20 degrees. However, it is also within thescope of the invention that steeper drum angles may be utilized.

[0119] Food product 115 enters the drum 111 on, e.g., an infeed conveyor116 (more generally, infeed device 1101) and discharges on a dischargechute 1121. UVC light is attenuated on the infeed (i.e., receiving) end1291, and on the discharge (i.e., outputting) end 1311 by the UVCbaffles 1191 which in the present embodiment includes a UVC attenuatingand/or reflective curtain substantially precluding the escape of UVClight from the drum 111. However, note that similar enclosures to theUVC attenuating baffles 1191 shown in FIGS. 1 and 2 may also be usedwith the present embodiment.

[0120]FIGS. 8A and 8B are, respectively, a side view and an food productdischarge end view of an additional embodiment of the present invention(referred to hereinbelow as the “square drum” embodiment) which utilizesan embodiment of the drum 111 having an inner drum 203 that has squarecross sectional shape. The inner drum 203 is fixedly attached to theinterior of a cylindrical exterior drum 113, or alternatively, the drum203 may be attached to the cylindrical rings 204 at, e.g., the locationsof drive belt 1141 and support wheels 121, and there are UVC lamps 161with reflector(s) 151 for irradiating foodstuffs 115 which may be gentlyrolled in the square drum 203. The drum 113 is supported on the floor bya structural frame 141 which in one embodiment is substantiallyidentical to the frame of the embodiments shown in FIGS. 1 and 2(although illustrated differently in FIGS. 8A and 8B). The UVC lamps 161and reflector(s) 151 are located inside the drum 203 and are supportedby an embodiment of the light support subassembly 1351 which, in thepresent square drum embodiment, is substantially a pair of frame crossmembers 1524 (one at each end of the drum 113) and preferably at leastone support member 114 that extends through the inner square drum 203and attaches to the cross members 1524. Accordingly, the reflector(s)151 and the electrical connections for the UVC emitters 161 are attachedto this support member 114. Of course, one or more embodiments of thelight assembly 145, and/or the light support subassembly 1351 may alsobe utilized with this square drum embodiment (as well as with most othernon-round shaped rotatable drums for surface sterilization). The drum113 is supported on a plurality of wheels 121 (at least three andpreferably four) wherein the wheels 121 are supported by the structuralframe 141. The wheels 121 provide the rotational support for the drum113 on the frame 141. The inclination angle of the drum 113 may beadjusted with adjustments to one or more drum inclination adjustmentscrews 131 as described above for the embodiments of FIGS. 1-3. Foodproduct 115 enters the drum 203 on an infeed device 1101 and isdischarged on a discharge device 1121 (e.g., a discharge chute or slide1123). UVC light is attenuated on the infeed drum end 1291 and on thedischarge drum end 1311 by the UVC attenuating baffles 1191, which inthe present embodiment is similar to the UVC attenuating or reflectivecurtains shown in FIG. 7. The rotational movement of drum 113 isprovided by the drive mechanism 171 (FIGS. 8A and 8) which is secured tothe frame 141. The transmission of rotational movement from the drivemechanism 171 to the drum 113 is provided by the belt drive sheave orpulleys 1201 and the drive belt 1141. Food product 115 on the inside ofthe square drum 203 is lifted and tumbled by the flat surfaces of thedrum 203 in the germicidal light created by the UVC lamps 161 and thereflector(s) 151. In an alternative embodiment, the drum 113 can beceiling mounted in the same manner as described in FIG. 7. The squaredrum embodiment may be used without the product tumblers 191. However,such tumblers 191 as described above may also be used in the square drumembodiment. Note that it is also within the scope of the presentinvention to provide other drum geometries in which the drum has aplurality of flat sides other than four, wherein a cross section of drum113 can be triangular, octagonal, hexagonal, etc.

[0121] A further alternative embodiment of the drum 111 is shown in FIG.9, wherein tumblers 191 may be interspersed and combined with a foodproduct advancing helical ribbon 1221 provided on the inside surface ofthe drum 111, wherein the drum rotates in the direction of arrow 117.The helical ribbon 1221 continuously wraps around the inside surface ofthe drum 111 so that together with the tumblers 191 (which may be atsubstantially right angles to the ribbon) tumble and advance thefoodstuff 115 in the presence of the UVC light from the lamps 161 withreflector(s) 151 for irradiating the foodstuff 115 while the foodstuffis being turned and tumbled in the drum. Note in some embodiments, thetumblers 191 need not fully span the distance between consecutiveflights of the ribbon 1221; e.g., such a tumbler may be segmented.Additionally, note that in some embodiments the helical ribbon 1221 mayalso be segmented (e.g., not continuous through the interior of thedrum).

[0122] The drum 111 of FIG. 9 may be used with UVC lamps 161 supportedin the same manner as described for the embodiments of FIGS. 1-3, orFIGS. 8A-8B. The drum 111 of FIG. 9 may be supported from the floor by astructural steel frame 141, as shown in FIG. 1A with all of its motors,drives and drum related supporting hardware, or it can be supportedoverhead as shown in FIG. 7 with all of its motors, drives and drumrelated supporting hardware. The helical ribbon 1221 in the embodimentof FIG. 9 can be of different pitches throughout the drum 111, or it canbe of a constant pitch (i.e., the distance between the flights 1221 canbe variable or constant). In an embodiment in which the pitch is shorterat the infeed end 1291, and the pitch becomes longer at a locationtoward the discharge end 1311, the food product 115 depth in the drumwill be reduced at the point the pitch is increased.

[0123] The retention time of the food product 115 in the drum 111 forsurface sterilization may be dependent upon various drum 111 parameterssuch as the inclination angle (if applicable) of the drum, the drumrotational speed, the configuration of the tumblers 191 (and/or anyhelical ribbon 1221), the amount of food product 115 in the drum, andthe amount of UVC energy emitted by the UVC lamps 161. In particular,the amount of UVC energy required to be output by the UVC emitters 161for appropriate surface sterilization of the food product 115 issubstantially determined by: (i) the retention time of the food product115 in the drum 111, (ii) the irradiance of the UVC light adjusted foroperating temperature and distance from emitter to foodstuff (typicallyrepresented in microwatts per square centimeter, as one of ordinaryskill will understand), and (iii) the surface area of the food product115 that is actually exposed to the UVC light. Since such UVC irradiancemay be measured in microwatts-second per centimeter squared, the tablehereinbelow shows the various amounts UVC (i.e., UVC at 253.7 nm)required to destroy 90% of some common organisms. TABLE 2 Germicidalenergy required to destroy common microorganisms. Microorganism Energy,μW-sec/cm² Bacteria Bacillus anthracis 4,520 Bacillus megaterium 1,300Bacillus megaterium spores 2,730 Bacillus subtills 7,100 Bacillussubtills spores 12,000 Corynebacterium diphtheriae 3,370 Escherichiacoli 3,000 Micrococcus lutea 19,700 Micrococcus spheroides 10,000Neisseria Catarrhalis 4,400 Proteus vulgaris 2,640 Pseudomonasaeruginosa 3,500 Pseudomonas fluorescens 8,000 Salmonella enteritidis4,000 Salmonella typhimurium 8,000 Serratia marcescens 2,420 Shigellsparadysenteriae 1,680 Spirillum rubrum 4,400 Staphylococcus albus 1,840Staphylococcus aureus 2,600 Streptococcus hemolyticus 2,160Streptococcus lactis 6,150 Streptococcus viridans 2,000 YeastsSaccharomyces cerevisiae 6,000 Saccharomyces ellipsoides 6,000 Brewer'syeast 3,300 Baker's yeast 3,900 Mold spores Aspergillus flavus 60,000Aspergillus glaucus 44,000 Aspergillus niger 132,000 Mucor racemosus17,000 Oospora lactis 6,000 Penicillium digitatum 44,000 Penicilliumexpansum 13,000 Penicillium roqueforti 13,000 Rhizopus nigricans 111,000

[0124] Moreover, note that it is believed that to achieve a 99.99% killrate of such micro-organisms, the irradiance required can be up to fourtimes greater, which generally equates to four times as many emitters161 in the drum 111. Thus, it is an aspect of present invention to beable to vary the irradiance levels within the drum 111 by, e.g., varyingthe number of emitters 161 that are activated during food productsterilization. For example, in the embodiments of the UVC light assembly145 corresponding to FIG. 5, there can be up to twelve emitters 161activated concurrently. However, various switches may be provided thatactivate only a portion of these emitters 161. Thus, e.g., only everyother emitter 161 of the UVC light assembly 145 of FIG. 5 may beactivated to thereby reduce the UVC irradiance by half, or only everythird emitter may be activate to thereby reduce the UVC irradiance toone-third. Note that such reductions may be useful in circumstanceswhere the micro-organism(s) to be inactivated are more sensitive to UVClight (e.g., Escherichia coli above), but where items of the foodproduct 115 have a very convoluted surface that may require additionalrotational time in the drum 111 in order to assure that substantiallyall surfaces have been appropriately exposed to the UVC light.

[0125]FIGS. 10A through 10D show some alternative cross sectionalconfigurations of the UVC lamps 161 and their corresponding reflectors151 (such configurations referred to as “UVC light/reflectorconfigurations” hereinbelow). These UVC light/reflector configurationscan be used in conjunction, e.g., with alternative embodiments of theUVC light assembly 145 described above, and/or with generally smallerembodiments of the rotating drum 111. Such alternative UVClight/reflector configurations may not be entirely enclosed as the UVClight assembly 145 is. However, since the UVC light/reflectorconfigurations are also intended to withstand the sanitizing activitieswithin a food processing facility, the power supplies and ballastsassociated therewith may be remotely mounted (e.g., outside of the druminterior) in a watertight, and corrosion resistant electrical enclosure(not shown), which is referred to in the industry as a NEMA 4×electrical enclosure. However, note that the UVC reflectors 151 of suchUVC light/reflector configurations are preferably manufactured of areflective and corrosive resistant material such as those identifiedhereinabove (e.g., polished stainless steel, aluminum, zinc, or coatingssuch as magnesium carbonate, magnesium oxide, chromium or nickel).Moreover, note that the reflector 151 of FIG. 10B has a cross sectionalshape that may be circular or alternatively parabolic.

[0126] Whether the reflector 151 is included in the UVC light assembly145 of FIG. 5, or included in an alternative UVC light/reflectorconfiguration, the reflector directs the radiated UVC light in thedirection of the food product 115. The direction and range of UVC lighttransmitted directly from the emitters 161 to the food product 115,and/or indirectly via the reflector(s) 151 is generally toward thebottom of the drum 111. However, the direction and range mayadditionally be angled in the drum rotation direction wherein the foodproduct 115 is being lifted and tumbled in the drum by the tumblers 191and/or any helical ribbon 1221. Accordingly, the dimensions, shapeand/or adjustability of the UVC light assembly 145 (e.g., FIG. 5),and/or the UVC light/reflector configuration may be dependent on:

[0127] (a) the length, height and/or angle(s) of the tumblers 191, e.g.,both the emitters 161 and the reflector(s) 151 must be spaced apart fromthe rotating tumblers 191 a sufficient amount so that there is nocontact with the tumblers;

[0128] (b) the desired distance between the food product 115 within thedrum 111 and the assembly or combination of emitter(s) and reflector(s).Note that both the emitters 161 and the reflector(s) 151 should bespaced apart from the rotating tumblers 191 (more generally, the druminterior surface and projections therefrom) a sufficient amount and sothat preferably the food product 115 in the drum 111 does not becomewedged or deformed due to concurrent contact with a tumbler (or the druminterior surface and projections therefrom), and one of the emittersand/or the reflector(s) (or an assembly thereof). Further note that, ingeneral, for a drum 111 of diameter of 1 to 8 feet, the distance of theemitters and/or reflector(s) from the food product 115 may range from 2inches to 36 inches; and

[0129] (c) the range within the drum interior where most of the foodproduct 115 aggregates during drum rotation. For example, the higher thetumblers 191 lift the food product 115 in the direction of drumrotation, the greater the light reflection range from the reflector(s)that may be desired on the interior drum in the direction of drumrotation.

[0130] In at least some embodiments of the invention, the UVC lightassembly 145 and/or another light/reflector configuration may beadjustable so that its minimum distance to the food product aggregatingportion of the drum interior can be varied. For example, UVC lightassembly 145 may be raised when used to sterilize broccoli and lower forsterilizing nuts. Referring to the embodiments of FIGS. 1-3, suchraising and lowing can be accomplished by various mechanical, pneumaticand/or electrical techniques. In particular, the vertical segment ofeach of the jointed arms 1357 may include concentric telescoping shaftswith squeeze clamps (such as is used on bicycle seat posts) for securingthe concentric shafts together at a desired length. Additionally, notethat the task of raising and lowering the UVC light assembly 145 and/oranother light/reflector configuration may be performed by activating oneor more motors (not shown) for, e.g., pneumatically or electricallyadjusting the concentric telescoping shafts described above.Furthermore, such adjustments may be controlled by an operator providinginput to the controller 1400.

[0131] In at least some embodiments of the invention, the UVC lightassembly 145 and/or another light/reflector configuration may beadjustable for widening or narrowing the extent of UVC light reflectedfrom the reflector(s) and then directly contacting the food product 115.For example, such reflectors 151 may be segmented into adjustable slatswhose reflective angles can be individually varied. Moreover, theadjustment of these reflective angles may be performed electronicallyvia the controller 1400 and motors (not shown) mounted within the UVClight assembly 145 or adjacent to such adjustable reflectors 151.

[0132] Moreover, for at least some embodiments of the invention, the UVClight assembly 145 and/or another light/reflector configuration may beadjustable on, e.g., the light support subassembly 1351 (or on themounting structure 1353) so that the interior portion of the drum 111receiving UVC light directly from the reflector(s) 151 can be varied bytilting the UVC light assemblies 145 (or another light/reflectorconfiguration); i.e., such an assembly or configuration may be tiltablymounted on the light support subassembly 1351 (or on the mountingstructure 1353) so that the UVC light radiated directly from thereflectors 151 can be shifted from one portion of the drum interior toanother portion. However, note that in most embodiments of theinvention, the UVC light support subassembly 1351 itself remains in afixed location and position, at least some embodiments of invention aresuch that each UVC lamp 161 and corresponding UVC reflector 151 remainin a constant position relative to the food product 115 being lifted andtumbled within the rotating drum 111.

[0133]FIG. 11 shows details of an alternative UVC emitter coupling 169Athat may be used in embodiments of the invention instead of theconnector 169 of FIG. 6. In particular, the coupling 169A may be used inan alternative UV light assembly 145 to the embodiments shown in FIGS.1-3, and 5. Such an alternative UV light assembly 145 may not have theUV emitters 161 aggregately enclosed within a surrounding watertighthousing as is the case with the UV light assembly embodiments of FIGS.1-3 and 5. Thus, to prevent contamination of the food product 115 incase of an emitter 161 breaking, each of the emitters 161 must beindividually enclosed in a plastic sleeve as was described previously.Furthermore, the coupling 169A includes a watertight slip tube 1281 thatprovides a watertight covering and seal thereby protecting theelectrical connection between the UVC light female connector 1361 andthe emitter 161 to be electrically connected thereto. In particular, thewater tight slip tube 1281 provides watertight protection during hotwater and/or chemical clean up activities that are common in foodmanufacturing plants. Note that such slip tubes 1281 may be made of heatshrinkable or elastic food grade rubber materials. In using thecouplings 169A, the UVC emitters 161 may be attached in a fixed positionto a light assembly base member (not shown). The couplings 169A allowfor easy removal and cleaning, or replacement of both the emitters 161and/or their reflector(s) 151.

[0134] Many food products are weighed, prior to packaging, on multipleselect scales. Such scales are common in industry, and are oftencircular in configuration (when viewed from above, i.e., in plan view)such that the food product 115 is provided on each scale substantiallyat its center. For food processing applications using such circularselect scales, the sterilization drum 111 may be ceiling mounted asshown in FIG. 7 so that the discharge chute 1121 of the sterilizationdrum 111 is located to deposit the sterilized food product 115 at thecenter of one of the circular scale areas.

[0135]FIG. 12 shows a block diagram of the controller 1400 and both thehigh level components therein for controlling the surface sterilizer181, and various high level components with which the controller 1400communicates. The controller 1400 includes a plurality of computationalmodules for monitoring and controlling not only the surface sterilizer181 but additionally monitoring and controlling various sensors anddevices for, e.g., providing food product 115 to the surface sterilizerand/or releasing the food product from the surface sterilizer. FIG. 12may be considered as illustrative of various embodiments of thecontroller 1400 in that: (a) it is not necessary that all componentsshown in FIG. 12 be provided for controlling and monitoring a givenembodiment of the surface sterilizer. Moreover, even thought thedescription of the controller 1400 and the components with which itcommunicates will be described in terms of a surface sterilizer 181 thatincludes a rotating drum as the sterilizing transport, it is believedthat after one of ordinary skill in the art has understood thedescription of the controller 1400 hereinbelow, that such an individualcould make and use a corresponding controller for other embodiments ofthe surface sterilizer 181 that include, e.g., a transport having anauger screw therein. Accordingly, the controller 1400 includes thefollowing components:

[0136] (a) A food product flow controller 1412 for monitoring andcontrolling the amount of food product 115 provided to the surfacesterilizer 181. The controller 1412 receives input from one or more foodproduct device(s)/sensor(s) 1416 that are upstream from the surfacesterilizer 181, wherein these device(s)/sensor(s) provide information asto the amount of food product 115 that is flowing toward the drum 111.In particular, such device(s)/sensor(s) 1416 may include food productweight or volume sensors. Moreover, the controller 1412 may output foodproduct flow signals to such device(s)/sensor(s) 1416 that includemechanisms for altering the rate at which the food product 115 isprovided to the drum 111. Thus, e.g., such a device 1416 may reduce orincrease a food product conveyor speed providing food product to thesterilizer 181. Additionally, the controller 1412 may receive signalsfrom a food product exit sensor(s) 1420 indicating the amount of thefood product 115 that is exiting the drum 111. Such sensor(s) 1420 may,e.g., provide weight or volume measurements of the exiting food product115. Thus, the food product flow controller 1412 may determine anestimate of the amount of food product in the drum 111. Note that inaddition to, or as an alternative to, the sensors 1420, there may be oneor more drum 111 weighing sensors whose output can be used forestimating the weight of food product within the drum 111.

[0137] Using such input from sensor(s) 1416 and 1420 (and/or any drumweighing sensors), the controller 1412 may, in one embodiment, predictwhether the amount of food product 115 to be the drum 111 at a futuretime will keep the drum loaded within a predetermined range, e.g., therange being set manually by an operator, or accessed from the foodproduct settings database 1422 described further hereinbelow, andwherein the predetermined range may be indicative of a desirable in-drumfood product weight, volume and/or depth of the food product. If thefood product 115 amount is not within the predetermined range, then thecontroller 1412 may increase (or decrease) the food product flow rate tothe drum and/or exiting the drum. Moreover, note that such a change mayalso require a change in the UVC irradiance of the emitters 161.Accordingly, prior to the controller 1412 requesting an increase in thefood product in the drum 111 and/or a higher flow rate through the drum,the controller 1412 may request that the food product sterilizationcontroller 1440 (described hereinbelow) determine whether an increase inUVC irradiance is necessary to continue to properly sterilize the foodproduct 115 after such an in-drum food product increase and/or flowrate. If the food product flow controller 1412 receives notificationfrom the food product sterilization controller 1440 that the desiredsurface sterilization rate can be maintained, the food product flowcontroller 1412 requests: (i) the food product sterilization controllerto perform any necessary emitter 161 irradiance changes (perhapsstarting at a future time), and (ii) instructs one or more food productflow devices to cause the food product within the drum 111 to increaseand/or to cause the food product flow rate through the drum to increase.

[0138] In addition, the controller 1412 may also receive input from oneor more in-drum load/blockage sensors 1424 wherein such sensors may beused with the food product exit sensor(s) 1420 to determine, e.g., theamount of food product 115 in the drum 111 (e.g., weight or volume),and/or whether there is a food product blockage within the drum 111.Such food product blockage sensors 1424 include the probes 1408, and/ornon contact ultrasonic distance probes with analog outputs, and/or theoptical or infrared sensors that sense light beams traversing the length

of the interior of the drum as described hereinabove. Accordingly, ifthere is a reduction in the amount of the food product 115 exiting thedrum 111 and the blockage sensors 1424 are frequently or continuouslytriggered, then it is likely that a blockage has occurred within thedrum 111. Accordingly, the food product flow controller 1412 may notifythe (any) operator via the operator interface and command interpretermodule 1428 (described further hereinbelow) and the operator display1432 (e.g., a computer terminal display) of such a blockage as well asprovide a message to the runtime safety controller 1436 (describedfurther hereinbelow) which, in turn, may shut down surface sterilizer181. Note that the food product flow controller 1412 may also receivesignals from the operator interface and command interpreter 1428instructing the controller 1412 to change the amount or rate of foodproduct 115 in route to the drum 111. Moreover, the controller 1412 mayalso receive signals from a food product sterilization controller 1440(described further hereinbelow) which monitors the food productsterilization effectiveness. In particular, sterilization controller1440 may request the food product flow controller 1412 to increase ordecrease the food product 115 flow to the drum 111 due, e.g., to adetermination that the food product in the drum is being sterilizedsubstantially faster or slower than is desired for effectivesterilization and utilization of the surface sterilizer 181.

[0139] (b) The food product sterilization controller 1440 for monitoringand controlling the surface sterilization of the food product 115 withinthe drum 111 so that the intended degree of inactivation ofmicro-organisms on the food product is consistently met. In particular,the sterilization controller 1440 may activate and/or deactivate UVCemitters 161:

[0140] (i) according to any manual override instructions from anoperator (via operator interface and command interpreter 1428),

[0141] (ii) automatically depending on (1) the amount of food product115 in the drum 111 (such information received from the food productflow controller 1412), (2) the amount of UVC irradiance being currentlyoutput by the emitters 161, (3) the in-drum temperature (which may beobtained from temperature sensor(s) 1444) in that it is well known thattemperature variations may effect the UVC irradiance of emitters 161,(4) in-drum water/humidity sensor(s) 1448; (5) emitter failure signal(s)1450 that may be received from amp meter measurements of the flow ofpower to the emitters, and/or (6) input from the food product settingsdatabase 1422, wherein this database includes and supplies in-drum datarelated to sterilization such as: (6.1) the data of Table 2 hereinabovefor the micro-organisms that are desired to be inactivated on theparticular food product 115 being sterilized, (6.2) the preferred rangein food product weight, volume and/or depth in the drum, (6.3) thedesired range in drum 111 rotation speeds, (6.4) the desired druminclination, (6.5) the desired range of in-drum temperatures, (6.6) thedesired range of in-drum humidity, and/or (6.7) the desired distancebetween the emitters 161 and the food product 115. Moreover, thedatabase 1422 may store, for each of a plurality of different foodproducts 115, corresponding collections of values such as (6.1) through(6.7).

[0142]  Note that the sterilization controller 1440 may route allemitter 161 activations through the runtime safety controller 1436described below.

[0143] Additionally, the sterilization controller 1440 may request achange to the drum 111 rotation rate in order to maintain a specifiedmicro-organism sterilization rate (e.g., rotate the drum slower toincrease sterilization due to an increased elapsed time the food productremains in the drum, and rotate the drum faster to decreasesterilization), and/or increase sterilizer 181 productivity. Thus, thesterilization controller 1440 may notify the motor interface 1456 of a(new) range of preferred drum 111 rotation speeds for the food product115 (such signals being routed through the safety controller 1436).Also, the sterilization controller. 1440 may notify a drum inclinationcontroller 1460 of a desired range (or new range) of drum 111inclinations for the particular food product 115 being sterilized. Notethat such notifications are also routed through the safety controller1436. Moreover, the sterilization controller 1440 may notify an operator(via the operator interface and command interpreter 1424, and theoperator display 1432) of sterilization irradiance, emitteractivation/deactivation, and/or emitter failures.

[0144] In at least some embodiments, the controller 1440 may retrieve,from the food product settings database 1422, sterilizer 181 operatingsettings for various individual food products, which the operator mayselect from a menu on the operator interface 1428.

[0145] In some embodiments of the invention there may be one or moreemitter output sensors 1464 that substantially directly measure theirradiance output by the emitters 161 such as described hereinabove as“germicidal in-drum concentration sensors”. Accordingly, thesterilization controller 1440 receives input from such sensors 1464 forestimating the amount of irradiance to which the in-drum food product isbeing exposed.

[0146] As an aside note that at least some embodiments of the invention,the sterilization controller 1440 is programmed to assure a UVCirradiance of at least 1.5 to 2 times the minimum irradiance necessaryto inactivate the targeted micro-organisms on the food product 115.Thus, it is assumed that variations food product sterilization factorsnot fully modeled will not be compensated effectively by such additionalUVC irradiance.

[0147] Additionally, circumstances may arise wherein unexpectedconditions occur during food product sterilization. For example, theoperator or the food product flow controller 1412 may request increasein the irradiance in 3 minutes due to an increase in food product to thedrum 111. However, if upon attempting to activate an additional emitter161 the emitter fails, then if no additional UVC irradiance can beobtained, there is the possibility of food product 115 not beingproperly sterilized. Accordingly, the food product sterilizationcontroller 1440 monitors such situations, and mitigates them to thedegree possible by requesting one of more actions that will increase theresidence time of food product 115 in the drum and/or reduce the amountof food product in the drum 111. In particular, one or more of thefollowing tasks may be performed:

[0148] (i) the food product flow controller 1412 and/or operator isimmediately notified to slow the influx of food product 115 to the drum111;

[0149] (ii) the motor interface 1456 may be notified to slow therotation of the drum 111; and/or

[0150] (iii) the drum inclination controller 1460 may be notified toreduce the inclination of the drum 111.

[0151] (c) The drum inclination controller 1460 for controlling andmonitoring the inclination of the drum 111, wherein this module providesthe interface between the (any) powered drum inclining device 1468(e.g., pneumatic, electrical or hydraulic device(s) for changing aninclination of the drum) and the other modules of the controller 1400.Note that the drum inclination controller 1460 may receive input from adrum inclination sensor 1469, wherein such input indicates the currentinclination of the drum 111. Additionally, the drum inclinationcontroller 1460 provides communication with the operator interface andcommand interpreter 1428 for receiving drum 111 inclination commands andfor outputting information indicating the drum's current inclination.Additionally, the drum inclination controller 1460 may communicate withthe safety controller 1436 for receiving permission to change theinclination of the drum 111. For example, in an embodiment of surfacesterilizer 181 wherein there are proximity detection sensors placed nearthe portions of the drum 111 that move when drum inclination changes,such sensors may signal the safety controller 1436 when there is anobject or person that is within an unsafe zone for drum movement tocommence and/or continue. Thus, the drum inclination controller 1460 mayquery the safety controller 1436 prior to initiating any druminclination changes, and additionally, may act on unsolicited messagesfrom the safety controller 1436 to terminate drum 111 inclinationmovement and/or reverse the drum inclination movement.

[0152] (d) The motor interface controller 1456 provides input to motorspeed governor 1470 for indicating when and at what speed the motor 173is to rotate. Additionally, the motor interface controller 1456 receivesinput from a motor rotation sensor 1472 for determining the currentmotor rotation speed. Commands for changing (and particular, increasing)the speed of the motor 173 may be routed through the safety controller1436 first. However, operator queries (and responses thereto) regardingmotor 173 related matters (e.g., rotational speed, and/or temperature)need not be routed through the safety controller 1436.

[0153] (e) The operator interface and command interpreter 1428 is theprimary interface between the operator and the other modules of thecontroller 1400. In particular, the operator interface and commandinterpreter 1428 receives and interprets operator commands from operatorcommand input device(s) 1472 directed to controlling various aspects ofthe food product 115 sterilization (e.g., changing the food product flowto the drum 111, changing the in-drum UVC irradiance, changing the druminclination, changing the drum rotation rate, and/or terminating thesterilization process such as in an emergency stop). For example, uponreceiving an operator command, the operator interface and commandinterpreter 1428 may interpret/parse the command, and then determinewhich submodule of the controller 1400 the resulting information shouldbe directed. Thus, an signal from the emergency stop button 1404 willcause a “stop” message to be sent to the safety controller 1436, whereasa request for information related to the food product 115 flowing intothe drum 111 (e.g., the weight per minute flowing into the drum) may bedirected to the report/log interface 1476. Note that, as statedhereinabove, substantially all operator commands for changing an aspectof sterilization process will be first routed to the safety controller1436 to obtain permission for the change, and subsequently, if suchpermission is granted, the command can then be forwarded to thesubmodule of the controller 1400 for performing the operator inputcommand. However, if the safety controller 1436 determines that, e.g., arecent sensor input indicates a possible condition that would endangerpersonnel in proximity to the surface sterilizer 181, then the safetycontroller 1436 will not forward the command for processing, but willinstead provide responsive communication to the operator (via theoperator interface and command interpreter 1428) that the command cannot be currently performed. Note that in addition to the emergency stopbutton 1404 (FIG. 1A), the operator interface and command interpreter1428 may receive input from input devices 1472 such as an operatormanipulateable computer pointing device (e.g., computer mouse), a touchscreen, voice recognition software, and/or a keyboard. Additionally, theoperator interface and command interpreter 1428 may receive operatorcommands for notifying the report/log interface 1476 (describedhereinbelow) to request the generation of a report/log from thesterilization log database 1480, e.g., related to the food product 115sterilization performed by the surface sterilizer 181. Furthermore, theoperator interface and command interpreter 1428 may output surfacesterilizer and/or food product related information to the operator viathe operator display 1432. Such outputs may be in response to anoperator query and/or a notification generated by one of the submodulesof the controller 1400 as one of ordinary skill in the art willunderstand. In particular, the operator interface and commandinterpreter 1428 may provide the operator (via the operator display1432) with a menu of selections identifying different food products 115for sterilization. Thus, the operator may provide input to the operatorinterface and command interpreter 1428 of the type of food product 115to be sterilized and the operator interface and command interpreter theninstructs the sterilization controller 1440 to retrieve the default (orlast used) surface sterilizer 181 operating parameter values from thedatabase 1422 and use the retrieved values for configuring thesterilizer 181 so that this food product can be sterilized.Additionally, the operator interface and command interpreter 1428 mayallow the operator to query, add, delete and/or modify the sterilizationsettings (e.g., such as (6.1)-(6.7) above) in the food product settingsdatabase 1422 for a selected food product 115.

[0154] (f) The report/log interface 1476 provides the other submodulesof the controller 1400 with access to contents of the sterilization logdatabase 1480. Moreover, the report/log interface 1476 allows theoperator to request sterilizer 181 performance information (real time orotherwise) such as: the amount of food product 115 sterilized within agiven time period, the UVC irradiance generated by the emitters 161, theestimated amount of UVC irradiance contacting the in-drum food product115, the average and/or range of time that individual food product itemsremain in the drum 111, the type of food product 115 sterilized, thetargeted micro-organism(s) for inactivation, the drum rotation speed,the drum inclination, surface sterilizer breakdown data (e.g., types anddates of breakdowns), and/or surface sterilizer 181maintenance/sanitation schedules. Note that this information may beretrieved from the sterilization log database 1480. Accordingly, thereport/log interface 1476 may be part of a database management systemthat includes programs for various predetermined reports and queries,wherein, e.g., SQL database queries are output to the sterilization logdatabase 1480. Also, note that in addition to the various data itemslisted above that can be accessed via the database 1480, reports may begenerated that also include such information as: the identification ofthe operator(s), and the sterilization productivity of the operator(s).Of course, for such reports/logs to be generated, data upon which thereports/logs are based must be accessible. Accordingly, although notshown, the controller modules 1412, 1428, 1436, 1440, 1460 and/or 1456may output substantially all drum 111 configuration and food productsterilization related measurements to the sterilization log database1480.

[0155] Similarly, the report/log interface 1476 may interface to thefood product settings database 1422 so that, e.g., an operator can viewand/or change: (i) the default settings for surface sterilization of theparticular food product 115, e.g., the default micro-organisms targeted,(ii) the default UVC irradiance to be used (which may be dependent uponthe amount of food product within the drum 111), (iii) the default drumrotation rate, and/or (v) the default drum inclination.

[0156] (g) The runtime safety controller 1436 is provided for assuringthe safe operation of the surface sterilizer 181. In particular, thesafety controller 1436 may receive signals from one or more of:

[0157] (i) Emergency stop switches 1484 such as emergency button 1404(FIG. 1A) wherein upon receiving such a signal the safety controller1436 shuts down all moving and UVC light generating components andadditionally may apply a brake for stopping drum 111 rotation. Thus, thesafety controller 1436 outputs a shutdown or deactivate signal to thedrive mechanism 170 by sending a shutdown message to the motor interface1456 which, in turn, translates this message into the appropriatedeactivate signal that is output to a motor speed governor 1470 thatcontrols the rotational speed of the motor 173. Additionally, the safetycontroller 1436 outputs a shutdown or deactivate signal(s) to the UVCemitter actuator(s) 1488 so that all UVC emitters 161 are deactivated.Note, that for the UVC light assemblies 145 such actuators are:electrical contactors located in the sterilizer control box 1406. Thesafety controller 1436 may also output a signal to a brake actuator 1492for applying a brake (e.g., of the braking assembly discussedhereinabove in the description of FIG. 1A) to stop drum 111 rotation.Moreover, the safety controller 1436 may also output a signal to one ormore alarm and/or alarm actuators 1496 for audibly sounding an alarm tobe heard by personnel in proximity of the surface sterilizer 181, and/orfor activating lights for also alerting such personnel. The safetycontroller 1436 may also send a message to the food product flowcontroller 1412 requesting that the flow of food product 115 to thesurface sterilizer 181 cease. Finally, the safety controller 1436 mayalso output data to the operator interface and command interpretermodule 1428 which, in turn, transmits one or more data messages fordisplay on one or more operator displays 1432 indicating that anemergency switch has been activated.

[0158] (ii) Baffle sensor(s) 1500 for providing signals as to whetherone of the UVC light attenuating baffles (e.g., baffles 1191) at one ofthe drum ends 1291 and 1311 has an open portion (which should be closed,e.g., a baffle door) such that UVC light could escape and harm personnelin proximity to the surface sterilizer 181. Upon receiving a bafflesensor 1500 signal indicating that there is an open baffle portion thatcould otherwise be closed, the safety controller 1436 may perform thesame functions as in the case of an activation of an emergency stopswitch(es) above except that: (1) there may be a reduction in the numberor kind of alarms activated, (2) the data message provided on theoperator display (via the operator interface and command interpreter1438) will indicate that a baffle portion must be closed before thesurface sterilizer 181 will be operable.

[0159] (iii) Motor guard sensor(s) 1504 for providing the safetycontroller 1436 with signals indicative of an object or person being tooclose to the drive mechanism 170, the rotating belt(s) 1141, and/or thewheels 121. Upon receiving such a signal, the safety controller 1436 maysound an audible alarm when a person or object is within a firstproximity to the drive mechanism 170, and at a nearer proximity stop themotor 173 and apply a brake to stop drum 111 rotation. Note that suchmotor guard sensor(s) 1504 can be electrical proximity sensors.Moreover, the motor guard sensor(s) 1504 may be provided in thefollowing locations: at the junction of the drive belt 1141 and the drum111, at the drive pulleys 1201, and at the support wheels 121;

[0160] (iv) Drum rotation sensor(s) 1508 for providing the safetycontroller 1436 with signals indicative of the rotational speed of thedrum 111. Note, that the output for the sensor 1508 should under normalsurface sterilizer 181 operation substantially correspond with theoutput from the motor rotation sensor 1472. However, in the event thatthe belt(s) 1141 slip or break from the drum or the pulley(s) 1201,and/or the motor 173 malfunctions (e.g., seizes), then a significantdifference between the output of the sensors 1472 and 1508 may cause thesafety controller 1436 to shutdown the surface sterilizer 181.

[0161] Referring to the operation of the various surface sterilizer 181embodiments above, the rotational motion of the drum 111 is caused by adrive motor 173 and transferred by power transmission components (e.g.,pulley(s) 1201) to the drum 111. As shown in FIG. 1A, there are drumsupport wheels 121 for rotatably supporting the drum. As shown in FIG.7, the ceiling mounted embodiment includes pulleys 1201 above the drum111 which cause the rotational motion of the drum by rotating the belts1141 about the circumference of the drum and from which the drum 111 issuspended. However, it is within the scope of the invention and wellknown to those in the art that there are various methods to cause therotational motion of the drum 111, such as timing belts, a roller chainand sprocket drives, v belts, etc. These components are readilyavailable from manufacturerers such as Baldor Motors and Drives, 5711 R.S. Boreham Jr. St., Fort Smith, Ark. 72908, Martin Sprocket and Gear,3100 Sprocket Dr., Arlington, Tex. 76015-2828, etc. The rotational speedof the drum is adjustable, e.g., via the controller 1400, and may alterthe retention time of the food product 115 in the drum being exposed tothe UVC light. In some embodiments, the drum 111 may be rotated using ACelectrical three phase motors, wherein rotational speed is determined byusing variable frequency electronic drives, which are common to thosefamiliar with the arts. Variable frequency drives are readily availablefrom manufacturers such as Allen-Bradley, 1201 South Second Sr.,Milwaukee, Wis. 53204-2410. Alternatively, variations in drum rotationalspeed using hydraulic motors may be accomplished with fluid flowadjustment valves, which are common to those familiar with the arts.Drum rotational speed may range from approximately one revolution perminute to approximately 120 revolutions per minute.

[0162] For a specific food product sterilization application, at some(and preferably most) of the following values are desirable to be knownin order to appropriately configure an embodiment of the surfacesterilizer 181 for the application: (a1) the food product 115 flow ratein, e.g., weight per unit of time (e.g., kilograms per minute), (a2) thefood product 115 bulk density in weight per unit of volume (e.g., poundsper cubic foot), (a3) the range in size of the individual food product115 items, (a4) a categorization of the food product surface texture(e.g., smooth to extremely convoluted), and (a5) the desired destructionrate for the most resistant targeted micro-organism(s) (e.g., bacteria,yeast, fungi, and/or mold spores). Such a configuration may additionallyuse measurements of: (b1) the drum 111 diameter (e.g., for determiningan expected and/or maximum food product 115 depth within the drum), (b2)the drum length (e.g., for determining the food product retention timewithin the drum and the UVC exposure time or dosage), (b3) the tumbler191 design (e.g., tumbler height and angle relative to the drumrotational axis), (b4) the drum inclination angle or range thereof(e.g., for determining food product retention time), (b5) the range indrum rotational speed, and (b6) the quantity, location, ambientoperating temperature, and wattage of the UVC emitters 161 to providethe required dosage to all surfaces of the food product 115 to achievethe desired destruction rate of the most resistant anticipatedmicro-organisms. Note that using the above values and measurementssettings may be initially established for surface sterilizing aparticular food product at a range of food product flow rates. Thus,initial settings can be determined for the UVC irradiance (e.g., thenumber of emitters 161 to activate), the distance of the emitters fromthe in-drum food product 115 from the emitters, and the expectedretention time within the drum 111 (while rotating within a particularrange of rotational velocities and inclined at a particular angle).

[0163]FIG. 13 is a flowchart of the high level steps performed by thecontroller 1400 during food product sterilization, and in particular fordetermining whether a change to the food sterilization process can besafely performed. Prior to startup of the sterilizer 181, in step 1802,the safety controller 1436 identifies the components of the sterilizerthat are required to be appropriately operable for safe operation of thesterilizer. Such identification may take place in two substeps: (1)identify the components that must be operable regardless of the foodproduct being sterilized (e.g., the motor 173, various ones of sensorsin FIG. 12, and the emergency button 1406), and (2) the components thatmust be sufficiently operable for the sterilizer 181 to operate safely,and to output a properly sterilized food product (e.g., a sufficientnumber of emitters 161 must be functional to obtain the desired UVCirradiance for the food product 115 that is to be sterilized). Sincesome embodiments of the surface sterilizer 181 may not include all ofcomponents shown in FIG. 12, the safety controller 1436 may access asterilizer configuration data file from, e.g., the food product settingsdatabase 1422 for identifying the required components of the surfacesterilizer 181 that must be operable for the safety controller 1436 todetermine that the sterilizer can be operated. Once such components havebeen identified, step 1804 is performed, wherein a determination is madeas to whether the safety controller 1436 has determined that it is safeactivate, reactivate and/or reconfigure all of the identified componentsof the surface sterilizer 181. Note that such components may be notcurrently active, or alternatively may be in an undesirable state andthus must be reconfigured. Subsequently, for each of the identifiedoperable components, the safety controller 1436 may access a runtimedata storage of descriptor (or “object” in object-oriented terminology)for determining:

[0164] (a) whether the component is currently active, available to beactivated, or partially (or wholly) inoperable, and

[0165] (b) for each component that is identified as not currently activeand is not identified as inoperable, the safety controller may query thecomponent for its operational status, and/or the controller 1436 maytest the component to determine its operational status and theoperational status of any associated sensors.

[0166] For most computer controlled embodiments of the sterilizer 181,the safety controller 1436 will query or test activate at least some ofthe following components upon initial startup of the sterilizer 181: themotor 173 (via the motor speed governor 1470), the emitters 161, the(any) drum inclination motor 1468, the emergency switches 1484, thealarm(s) and/or their actuators 1496, the in-drum food productload/blockage sensor(s) 1424, the food product drum in-feeddevices(s)/sensor(s) 1416, the food product exit sensor(s) 1420, thein-drum water/humidity sensor(s) 1448, the baffle sensor(s) 1500, andthe motor guard sensor(s) 1504. Moreover, if actual activation isperformed of, e.g., the motor 173, the emitters 161, and the druminclination motor 1468, then substantially all the other sensors shownin FIG. 12 can be tested.

[0167] If step 1804 determines that the sterilizer 181 is unsafe tooperate, then step 1808 is performed wherein various alerts,notifications and/or alarms may be initiated for indicating to theappropriate personnel that the sterilizer 181 is not safe to operateand/or can not be reconfigured as requested. In particular, if there isan operator, then the operator will be notified. Moreover, if step 1804was performed when attempting to startup the sterilizer 181 then thestartup will fail. Alternatively, if step 1804 was performed due to arequest to reconfigure one or more components of the sterilizer 181(e.g., that is currently operating), then these components will not bereconfigured. Subsequently, in step 1812, data indicative of why thesafety controller 1436 would not allow components to beactivated/reconfigured is written to the log database 1480 (in FIG. 12no data communication arrow is shown representing such communication inorder to simplify the figure). Then in step 1814, the safety controller1436 waits for additional input from, e.g., an operator or otherpersonnel for requesting that the safety controller 1436 again performstep 1804.

[0168] Alternatively, if step 1804 determines that the sterilizer 181 issafe to operate, then in step 1816 the safety controller 1436 sendsmessage(s) to one or more other components of the sterilizer 181requesting activation and/or reconfiguration. Moreover, the safetycontroller 1436 may also output corresponding to the (any) operatorindicating that the sterilizer 181 is safe to operate and/or has beenreconfigured as requested, and additionally output corresponding data tothe log database 1480. Subsequently, in step 1820 the safety controller1436 waits for additional input. Note that substantially all sterilizer181 (re)configuration commands input by the (any) operator, and(re)configuration requests by any sterilizer component (e.g., the foodsterilization controller 1440, the food product flow controller 1412,the motor interface 1456) are routed back through the safety controller1436.

[0169] Assuming the safety controller 1436 receives input, then in step1824, this input is logged to the log database 1480. Following suchlogging, in step 1828, a determination is made as to whether thereceived input is from a sensor (or combination of sensors) indicatingthat a problematic event has occurred that can not be automaticallycorrected while operating sterilizer 181. Note that the sterilizer 181configuration files may include data specifying which sensor input (orcombinations of sensor inputs) is severe enough to result in a positiveoutcome from step 1828. However, at least the following are deemedsufficiently severe: (i) insufficient UVC light capacity to provide thedesired sterilization, (ii) the emergency button 1404 is activated,(iii) one of the UVC baffles 1191 is not fully closed, (iv) drum 111rotation does not correspond with motor 173 rotational speed and/ordirection, (v) a motor safety guard sensor 1500 is activated, (vi) anin-drum blockage is detected. Accordingly, if the result from step 1828is positive, then in step 1832 the sterilizer 181 is shutdown, and instep 1836 any appropriate alarms and/or notifications are initiated bythe safety controller 1436. Thus, an operator will be notified, andlikely any personnel that are responsible for food product 115processing that are upstream from the sterilizer 181 may be notified.Subsequently, in step 1840, the safety controller 1436 instructs thefood product flow controller 1412 to stop the flow of the food product115 to the sterilizer 181. Then step 1844 is performed, wherein theaction(s) taken are logged in the sterilization log database 1480, andthe safety controller 1436 once again waits for input (step 1820).

[0170] Returning to step 1828, if the safety controller 1436 determinesthat input does not identify a sufficiently severe event to warrantshutting down the sterilizer 181, then in step 1848 a determination ismade as to whether the received input indicates that a correction of apreviously identified anomalous event has occurred. Such a correctionmay be for an event that previously shutdown the sterilizer 181 such asa UVC baffle 1191 not being fully closed, an activation of the emergencybutton 1404, or an in-drum blockage detected. However, there are alsoother anomalous events that may also occur that are not sufficientlysevere by themselves to warrant shutting down the sterilizer 181, suchas: (i) an emitter 161 failure (which may or may not be a severe enoughevent to shutdown the sterilizer 181 depending on whether there is stillsufficient UVC light being generated to continue sterilization orwhether there is a spare emitter that can be activated while thesterilizer 181 is sterilizing), (ii) the in-drum temperature is out ofrange (and there is a drum temperature conditioner that can beactivated), (iii) there is a reduced supply of food product 115 beingprovided to the drum 111, (iv) a warning proximity sensor is activatedwherein an object or person has come too near to the sterilizer 181 (ora portion thereof, e.g., the motor 173) but the object or person is notso close to warrant sterilizer shutdown. However, lights and/or alarmsmay be activated.

[0171] If it is determined in step 1848 that a correction of apreviously identified anomalous event has been performed, then in step1852 the input is used to update the runtime sterilizer state data usedby the safety controller 1436. Thus, e.g., the input may be indicativeof a faulty emitter 161 being replaced with a new emitter. Accordingly,the sterilizer state data (also known as configuration data) is updatedto reflect a new UVC irradiance capacity that can be generated bysterilizer 181. Alternatively, the input may be indicative of a personor object moving out of the range for activation of the above-mentionedwarning sensor, and thus, e.g., any lights and/or alarms may bedeactivated. The input may instead be indicative of a change in the flowof food product 115 into the drum 111 so that the flow is again within apreferred operational range. Accordingly, since the sterilizer 181 mayhave been reconfigured to process the unpreferred food product flow(e.g., the drum 111 rotation, UVC irradiance and/or drum inclination mayhave been changed, or, the sterilizer 181 may have been configure tobecome intermittently inactive until one of: (i) an predetermined amountof food product 115 resided in the drum 111, or (ii) a predeterminedamount of time expired), the sterilizer state must updated to reflectthe more desirable food product flow rate. Subsequently, step 1804 isagain performed.

[0172] Alternatively, if the result from step 1848 is negative, then instep 1856 a determination is made as to whether the safety controller1436 has received an input from an operator. If so, then in step 1860 adetermination is made as to whether the operator input is for requestinga configuration change to the sterilizer 181, or for requestinginformation such as operational status information. If the operatorrequest is for information only, then the request is honored in step1864, and subsequently steps 1844 and 1820 are again performed.Alternatively, if the operator request is for a reconfiguration of thesterilizer 181, then in step 1868 a determination is made as to whetherthe requested change is safe (both in terms of operation of thesterilizer 181 and to achieve the desired degree of food product 115sterilization). Note that the processing performed in step 1868 may besubstantially similar to the processing performed in step 1804 describedabove. Accordingly, if the safety controller 1436 determines that therequested change(s) are safe, then in step 1872 the controller 1436sends messages to other components of the controller 1400 requestingthem to perform various portions of the operator's request. Thus, anoperator request to increase the food product flow through thesterilizer 181 can result in the safety controller 1436 requesting (instep 1868) that the food product sterilization controller 1440 determinean appropriate increase in the UVC irradiance for the new food productflow rate and subsequently return to the safety controller: (i) arequest for activation of a corresponding number of additional emitters161, and (ii) a new drum 111 rotation speed and/or a new druminclination. Thus, once the safety controller 1436 determines that theresponsive output from the food product sterilization controller 1440 issafe and within the capability of the sterilizer 181, then (in step1872) the safety controller forwards and/or generates the appropriatemessages to the UVC emitter actuator(s) 1488, the motor interface 1456and/or drum inclination controller 1460 to accomplish the operator'srequest. Then, after step 1872, steps 1844 and 1820 are again performed.Thus, an input from an operator may receive preference over sterilizer181 operational parameter values determined by, e.g., the foodsterilization controller 1440.

[0173] Alternatively, if (in step 1868) the safety controller 1436determines that the operator's request is unsafe, then in step 1876 theoperator is alerted that the request is unsafe, and preferably adescription of why is also provided to the operator.

[0174] Returning now to step 1856, if the result from this step is thatthe input is not from the operator, then in step 1880 a determination ismade as to whether the input is from another module of the controller1400 wherein the input was not initiated by an operator. In particular,since the controller 1400 may provide various capabilities forautomatically reconfiguring the sterilizer 181, step 1880 is foridentifying such automatic reconfiguring requests. If step 1880determines that the request was really a result of a previous operatorrequest, then step 1868 is again performed for determining which one ofthe steps 1872 and 1876 should be performed. Alternatively, if the inputrequest is automatically generated by another one of the controller 1400modules (e.g., the food product sterilization controller 1440), then instep 1884 a further determination is made as to whether the input is forrequesting a change in the configuration of the sterilizer 181. If so,then in step 1888 a determination is made as to whether the automaticreconfiguration is acceptable to the operator. Note that it is an aspectof at least some embodiments of the controller 1400 that the operatorcan request to view and accept or reject at least some of the automaticconfiguration changes generated by the controller 1400. Such operatorintervention allows the operator to provide input to override (orreceive preference over) certain automatic configurations (e.g., theamount of UVC light emitted, the drum 111 rotation rate, and/or the druminclination) and thereby insert operator experience and intelligenceinto the control of the sterilizer 181. Thus, the operator may be ableto set a minimum UVC irradiance that is above the setting typically usedon the particular food product 115 being sterilized and increase thedrum 111 rotation rate (e.g., due to a backlog in food product 115 thatmust be sterilized). Accordingly, if the food product sterilizationcontroller 1440 requests a reduced UVC irradiance and drum rotation ratebelow what the operator specified, then the request will not be honored,and instead the operator may be notified of the controller 1440 request(step 1892). Alternatively, if in step 1888 it is determined that theautomatic reconfiguration is acceptable to the operator (either due tothe operator not supplying a constraint applicable to the currentautomatic reconfiguration request, or due to the request satisfying suchan operator additional constraint), then step 1868 and steps followingare performed as described above.

[0175] Returning to step 1884, if it is determined that the input fromanother module of the controller 1400 is not a request ofreconfiguration of the sterilizer 181, then in step 1896 the request ishonored and steps 1844 and 1820 are again performed.

[0176] It is important to note that the controller 1400 may be used tocontrol a plurality of sterilizers 181. Thus, a large food processingfacility may operate a two or more sterilizers 181 and there may be asingle controller 1400 controlling both sterilizers. A single controller1400 controlling a plurality of sterilizers 181 can be particularlybeneficial in that if the controller can route a food product 115 fromone sterilizer 181 to another sterilizer, then the food processingoperation is not as sensitive to a malfunction of a sterilizer in thatthe controller can reroute the food product to another one of thesterilizers and thus food processing is not halted.

[0177] The following examples illustrate various uses and configurationsof the sterilizer 181. Note that drum 111 rotation rate and inclinationin these examples may be controlled by an embodiment of the controller1400 for maintaining the desired degree of food product surfacesterilization.

EXAMPLE 1 French Fried Frozen Potatoes in a Rotary Drum

[0178] Frozen, partially fried, shoestring French fried potato stripsare to be surface sterilized prior to being provided to a multipleselect scale unit, which is circular from a plan or overhead view. Sincethis food product is to be introduced to the center of the scale unit,an embodiment of the sterilizer 181 which is supported from above (as inFIG. 7) is selected to facilitate the drum 111 being above the multipleselect scale. Assuming the potato strips are frozen, and are beingsterilized in an unconditioned ambient atmosphere, the drum 111 may beinsulated to prevent condensation on the exterior of the drum, whereinthe condensation could drip onto the potato strips on the multipleselect scale. The flow rate of the potato strips through the drum 111 islimited by the scale to no more than 50 weighments per minute of 6.5pounds per weighment, or a flow rate of 325 pounds of potato strips perminute (50 weighments/minute*6.5 lbs/weighment). Bulk density of thepotato strips is 19 pounds per cubic foot; therefore, the volume flowrate is 17.1 cubic feet per minute (325 lbs/minute*1 ft³/19 lbs).

[0179] The sterilizer 181 is configured to kill 99% of Listeriamonocytogenes bacteria at a UVC dosage of 19,000microwatts-seconds/centimeter squared. At this UVC dosage, the exposuretime is expected to be 8 seconds for each surface of each of thetumbling potato strips. UVC irradiance sterilization efficiency isreduced to 33% to assure all surfaces of each potato strip areadequately exposed to the UVC germicidal radiation. Therefore, theexposure cycle time for the flow of potato strips through the drum 111may be no less than 24 seconds (8 seconds exposure*1/0.33 efficiency).At a volume flow rate of 17.1 cubic feet per minute, and a 24-secondexposure cycle time, the volume of potato strips per exposure cycle isno more than 6.8 cubic feet/exposure cycle (24 seconds/exposure cycle*1minute/60 seconds*17.1 ft³/minute). A drum 111 having a diameter of 48inches and a drum length of 8 foot long is selected, wherein there aresix equally spaced tumblers 191 about the interior surface of the drum111. The tumblers 191 within the drum 111 are selected to be 4 inches inheight. Thus, a food product average depth of no more than 4 inches forthe potato strips is preferred due to the height of the tumblers 191.Thus, when the potato strips are being tumbled within the drum 111, theyare lifted or contacted by at least two of the six tumblers 191 at alltimes. The depth of potato strips in the bottom 60 degrees of the drum111, from the 6:00 position to the 4:30 position assuming a counterclockwise rotational direction, is anticipated to be 4 inches. Due tothe tumbling action of the potato strips, the depth as the drum 111rotates from the 4:30 position to the 3:00 position, assuming a counterclockwise rotational direction, is anticipated to average approximately2 inches. Therefore, the average cross sectional depth of the potatostrips in the drum 111 is 3 inches. With the drum 111 being 8 feet long,the maximum quantity of potato strips in each cycle is equal to 8.4cubic feet (3.14*48 inch*1 ft/12 inches*120 degrees/360 degrees*8 ft*3inches*1 ft/12 inches). Since 8.4 cubic feet is greater than the volumeof potato strips per exposure cycle (i.e. 6.8 cubic feet/exposurecycle), it is believed that the drum configuration will be adequate forthe expected flow rate of potato strips. The exposure area of the potatostrips in the drum 111 at an average product depth of 3 inches isapproximately 117 square feet (3.14*(48 inches−6 inches)*1 ft/12inches*120 degrees/360 degrees*8 ft*4 times) based on 120 degrees of theinside drum radius, reduced by the average depth of the potato stripsfor an effective diameter of the potato strips exposed to the UVC lightassembly 145, by 8 feet long by four times to account for the four sidesof the tumbling French fry potato strips within the drum, at least oneof these sides exposed to the UVC light at any time. Assume that aquantity of (24) UVC emitters 161 are selected at 24 inches long each,wherein these emitters are mounted within the drum 111 so that they arearranged to be offset from the exposed potato strips by 6 inches, or arange of 9 to 10 inches from the inside radius of the drum. Furtherassume that the UVC energy level of each emitter 161 is 50 watts, andthat this energy level is de-rated to 80% energy for the refrigeratedambient temperature inside the drum caused by the flow of the frozenpotato strips, and additionally de-rated to 40% due to the distance fromthe emitters to the exposed potato strips. Therefore, the effectiveenergy contacting the potato strips after the cumulative adjustments fortemperature and distance is 16 watts/emitter (50 watts/emitter*0.8temperature derate*0.4 distance derate), or a total of 384 watts (16watts/emitter*24 emitters) from the 24 emitters. Thus, UVC energy forirradiating the potato strips is approximately 28,263microwatts-seconds/cm² (384 watts*8 seconds*{fraction (1/117)} ft²*1ft2/929 cm²*1,000,000 uw/w) resulting in a safety factor of 1.5 for the99% target kill rate of Listeria monocytogenes. Inclination angle anddrum rotational speed are adjusted so that the potato strips indeed flowthrough the drum with a 24 second exposure cycle time. Since the Frenchfried potato strips were partially fried in 350 degree Fahrenheit oilprior to freezing; therefore, the interiors of the potato strips havebeen thermally sterilized. Accordingly, with the application of thesurface sterilization process provided by the sterilizer 181 immediatelybefore the packaging of the potato strips, any bacteria thatre-contaminated the surface of the potato strips will be killed orinactivated at a 99% destruction rate. Therefore, the potential forpotato strip waste, recall from market, bio-terrorism and consumerillness from consumption of contaminated potato strips is greatlyreduced. In recent years, improvement in the testing and detection ofbacteria in foodstuffs have provided for the detection of much smallerconcentrations of bacteria; therefore, due to increasingly smalleramounts of detected bacteria, there has been increased cost to the foodprocessing industry associated with product waste, recalls, and consumerclaims. The present invention as demonstrated in this examplesubstantially solves surface contamination of food products.

EXAMPLE 2 Raw Potatoes to a Potato Storage in a Rotating Drum

[0180] Raw potatoes are to be surface sterilized after being harvestedfrom an agricultural field, and prior to being provided to a storagebuilding. Since the potatoes are delivered with a truck, an embodimentof the sterilizer 181 which is supported from the floor or ground level(as in FIG. 1A) is selected. Since the potatoes are harvested as a rootcrop from underground in an agricultural field, an embodiment with aperforated drum 111 is selected to separate any loose dirt from thepotatoes. Attenuating baffles 1191 are installed around the entiresterilizer 181 to contain the UVC light used with the perforated drum111. The sterilizer 181 is to be integrated into an existing series ofequipment, which receives the potatoes from the transport truck, removesdirt and vines, and conveys the potatoes into a bulk storage building.The potato flow rate for unloading transport trucks into the storagebuilding is limited to no more than 160,000 pounds of potatoes per hourbased on transport truck unloading capabilities. Bulk density of the rawpotatoes is 40 pounds per cubic foot; therefore, the volume flow rate is67 cubic feet per minute (160,000 lb/hr*1 hr/60 minutes*1 ft³/40 lb).

[0181] The sterilizer 181 is configured to kill 90% of Aspergillus nigermold spores at a UVC dosage of 132,000 microwatts-seconds/centimetersquared. At this UVC dosage, the exposure time is expected to be 8seconds for each tumbling potato. UVC irradiance sterilizationefficiency is reduced to 33% to assure all surfaces of each potato areadequately exposed to the UVC germicidal radiation. Therefore, exposurecycle time for the flow of potatoes through the drum 111 may be no lessthan 24 seconds (8 seconds exposure*1/0.33 efficiency). At a volume flowrate of 67 cubic feet per minute, and a 24 second exposure cycle time,the volume of potatoes per exposure cycle is no more than 27 cubic,feet/exposure cycle (24 seconds/exposure cycle*1 minute/60 seconds*67ft³/minute). A drum 111 having a diameter of 6 feet and drum length of12 feet is selected, wherein there are six equally spaced tumblers 191about the interior surface of the drum 111. The tumblers 191 within thedrum 111 are selected to be 6 inches in height. Thus, a food productheight of no more than 6 inches for the potatoes is preferred due to theheight of the tumblers 191. Thus, when potatoes are being tumbled withinthe drum 111, they are lifted or contacted by at least two of the sixtumblers 191 at all times. The depth of potatoes in the bottom 60degrees of the drum 111, from the 6:00 position to the 4:30 positionassuming a counter clockwise rotational direction, is anticipated to be6 inches. Due to the tumbling action of the potatoes, the depth as thedrum 111 rotates from the 4:30 position to the 3:00 position, assuming acounter clockwise rotational direction, is anticipated to averageapproximately 4 inches. Therefore, the average cross sectional depth ofthe potatoes in the drum 111 is 5 inches. With the drum 111 being 12feet long, the maximum quantity of potatoes in each cycle is equal to 31cubic feet (3.14*6 ft*120 degrees/360 degrees*5 inches*1 ft/12 inches*12ft). Since 31 cubic feet is greater than the volume of potatoes perexposure cycle (i.e. 27 cubic feet/exposure cycle), it is believed thatthe drum configuration will be adequate for the expected flow rate ofpotatoes. The exposure area of potatoes in the drum 111 at an averageproduct depth of 5 inches is approximately 130 square feet (3.14*(72inches−10 inches)*1 foot/12 inches*120 degrees/360 degrees*12 ft*2),wherein this is based on: (i) the potatoes occupying 120 degrees of theinside radius, (ii) the radius to the potatoes is reduced from the druminside radius by the average depth of the potatoes for an effectivediameter of 62 inches for the potatoes exposed to the UVC light assembly145, (iii) the drum being 12 feet long, and (iv) a factor of two toaccount for the oval shape of the potatoes providing a contoured profilein the drum 111. An oval potato that is 2 inch diameter by 4 inches isapproximately 4 ounces or 0.25 lb each. Using the bulk density of 40lb/ft³ and 27 ft³ per exposure cycle, there are 1080 lbs of potatoes perexposure cycle (40 lb/ft³*27 ft³/exposure cycle), or 4320 potatoes perUVC exposure cycle at 4 ounces per potato (1080 lbs/exposure cycle*16oz/lb*1 potato/4 oz). If each potato has an exterior surface area of15.5 in², then the total potato surface area per exposure cycle is 465ft² (4320 potatoes/exposure cycle*15.5 in²/potato*1 ft²/144 in²).Assuming 130 ft² of this area is exposed to the germicidal light at anygiven time, this equates to 28% of the available area is exposed to thelight, which is approximately equal to the 33% irradiance sterilizationefficiency (ratio of 33%/28% equals 1.2, which compares to the safetyfactor in the calculation of UVC energy for irradiating the potatoes).On harvested potatoes, the percentage of available area will increasedue to the larger potatoes randomly mixed with the smaller potatoes ascompared to the above evaluation based on all smaller 4 ounce potatoes.Initially assume that a quantity of (240) UVC emitters 161 are selectedat 24 inches long each, wherein these emitters are mounted within thedrum 111 so that they are arranged to offset from the exposed potatoesby 6 inches, or a range of 11 to 12 inches from the inside radius of thedrum. Further, assume the energy level of each emitter 161 is 50 watts,and that this energy level is de-rated to 80% energy for therefrigerated ambient temperature inside the drum 111 during fall orwinter operations, and additionally de-rated to 40% due to the distancefrom the emitters to the potatoes. Therefore, the effective energycontacting the potatoes after the cumulative adjustments for temperatureand distance is 16 watts/emitter (50 watts/emitter*0.8 temperaturederate*0.4 distance derate), or total 3,840 watts from the 240 emitters.Thus, UVC energy for irradiating the potatoes is approximately 254,367microwatts-seconds/cm² (3,840 watts*8 seconds*{fraction (1/130)} ft²*1ft²/929 cm²*1,000,000 uw/w), which is sufficient (i.e. more than thedosage of 132,000 microwatts-seconds/cm²), resulting in a safety factorof 1.9 for the 90% target kill rate of Aspergillus niger. Inclinationangle and drum rotational speed are adjusted so that the potatoes indeedflow through the drum with the 36 second exposure cycle time for the 18foot long drum 111. With application of the sterilizer 181 immediatelyprior to the storage of the potatoes, there is a reduction of mold,fungi, and bacteria on the surface of the potatoes. Note that such areduction in potato surface micro-organism contaminates is believed toreduce damage in stored potatoes since mold, rot, and spoilage grows andexpands substantially from such potato surface contaminates during thestorage of the potatoes. Further note that a single one of the potatosurface micro-organism contaminates, the silver scurf disease (a surfacefungi found on potatoes) was estimated to have caused 7 to 8.5 milliondollars of damage to the Idaho fresh pack potato industry based on a1993 University of Idaho economic assessment. Accordingly, the presentinvention will provide the potato industry with a method and apparatusto minimize costs associated with surface molds, fungi, and bacteria onstored potatoes.

[0182] A second embodiment of the surface sterilizer 181 will now bedescribed with reference to the FIGS. 14 through 16.

[0183]FIG. 14 is a isometric view of a screw conveyor embodiment of thesurface sterilizer 181 (denoted herein as screw conveyor sterilizer1600) having a trough 1604 with an auger assembly 1608 therein. Theauger assembly 1608 includes an auger shaft 1612, a plurality of augerflights 1616, and a plurality of lifting tumblers 1620 (that performsubstantially the functions within the screw conveyor sterilizer 1600 asthe tumblers 191 perform in the drum surface sterilizer 181 embodimentsdescribed above). The auger shaft 1612 has a longitudinal extent thattraverses substantially the entire length of the trough 1604 (alsodenoted as a “transport” in, e.g., the Summary section above) from afood product infeed device 1624 to a food product discharge device 1628.Each of the auger flights 1616 spans substantially an entire crosssectional extent of the trough 1604 (such cross sectional extent beingtraverse to the length of the trough). Moreover, each auger flight 1616is obliquely angled relative to the longitudinal extent of the augershaft 1612 and is fixedly attached thereto so that when the auger shaft1612 rotates about an axis 1632 coincident with the shaft's longitudinalextent, the auger flights urge the food product 115 between adjacentflights toward the discharge device 1628. There may be a plurality ofthe lifting tumblers 1620 between the flights 1616, wherein the tumblers1620 both lift and tumble the food product 115 while the flightsfacilitate in conveying the food product toward the discharge device1628 and, importantly, also facilitate in exposing additional surfacesof the food product to a germicidal such as UVC light provided by one ormore UVC emitters 161 in combination with a lid/reflector subassembly1636 mounted over the trough 1604 and the auger assembly 1608. That is,emitters 161 generate the UVC light and the lid/reflector 1636 has a UVCreflective surface (such as the reflective surfaces describedhereinabove) that face the emitters for directing the UVC light towardthe food product 115 that is conveyed, lifted, and tumbled through thescrew conveyor sterilizer 1600. Moreover, note that the lid/reflectorsubassembly 1636 may be hinged to one side of the top of the trough 1604so that this subassembly can serve to reliably enclose the food product115 within the screw conveyor sterilizer 1600 (when closed on top of thetrough 1604), and provide access to the emitters 161 and/or the interiorof the screw conveyor sterilizer 1600 for, e.g., emitter replacement,reflector cleaning, and/or trough 1604 cleaning. Additionally, note thatthe emitters 161 be may fully enclosed in a watertight emitter enclosuresubstantially similar to the UVC light assembly 145 describedhereinabove. However, instead of the emitters 161 being in a convexarrangement within the UVC light assembly 145, the emitters for thescrew conveyor sterilizer 1600 may be in a substantially planararrangement, or the emitters may be in a concave arrangement within theemitter enclosure so that the emitters generally follow the contour ofthe reflective surface 1640 of the lid/reflector subassembly 1636.

[0184] During operation of the screw conveyor sterilizer 1600, therotational motion of the auger assembly 1608 is created by a drivemechanism 1644 (not shown, but which is well known in the art). At theends 1648 of the trough 1604 there are food product enclosing ends(known in the art as “end bells”) which prevent the food product 115from spilling out the ends of the trough 1604. In particular, there isan end bell 1652 at the food product input end of the trough 1604, andthere is an end bell 1656 at the food product output end of the trough1604. Additionally, there are auger support bearings 1660 mounted oneach end bell, wherein each end bell and it's attached bearing 1660provides the functionality for holding the auger assembly 1608 so thatit rotates about the axis 1632 in the trough 1604 as one of ordinaryskill in the art will understand. Moreover, each end bell 1652 and 1656is supported within the trough ends as one of ordinary skill willunderstand. The food product 115 enters the infeed device 1624 fallsthrough an opening 1664 in the bottom thereof into the trough 1604wherein it is tumbled (via tumblers 1620) while being transported thelength of the trough to the opposite end 1648. When this opposite or“output end” of the trough 1604 is reached, the food product 115 will beappropriately sterilized and will exit through an opening 1668 in thebottom of trough thereby entering the chute 1670 and is then depositedon the discharge device 1628.

[0185]FIG. 16 shows an inclined embodiment of screw conveyor sterilizer1600, wherein the food product 115 is transported from the lower(receiving) end 1672 of the screw conveyor sterilizer to its upper(discharging) end 1676. However, embodiments of the sterilizer 1600 maybe horizontal or reversely inclined (i.e., the receiving end 1672 ishigher than the discharging end 1676) as well. The end bells 1652 and1656 carry the bearings 1660 and the end bells are fixed (bolted orwelded) to the trough 1604 so that the auger assembly 1608 can rotatewithin the trough without hitting or rubbing the walls of the trough.

[0186] In FIG. 16, food product 115 enters the screw conveyor sterilizer1600 from an infeed device 1624 which includes a conveyor 116 and foodproduct storage hopper 1680 (this hopper also functioning to prevent thefood product 115 from spilling out of the receiving end 1672 of thescrew conveyor sterilizer 1600). In at least one embodiment, the productinfeed device 1624 may be a material handling apparatus, such as ashaker conveyor, belt conveyor, auger conveyor, etc. which provides aneven flow of foodstuff 115 to the screw conveyor sterilizer 1600. Thedischarge device 1628 may be attached to an auger support structure1684. Moreover, the discharge device 1628 may be a conventional foodproduct conveyor as one skilled in the art will understand.

[0187] Since the ends of the screw conveyor sterilizer 1600 may bepartially open (e.g., openings 1664 and 1668), there is the possibilityof UVC light escaping from the interior of the screw conveyorsterilizer. Accordingly, at least in areas where an operator and/orother personnel may be subject to such radiation, the UVC issubstantially prevented from exiting the volume enclosed by the screwconveyor sterilizer 1600. In particular, the lid/reflector subassembly1636 may have a shape and be fabricated from a material that effectivelyprevents harmful radiation from exiting through it and at the seam orcontact points with trough 1604. Additionally, the UVC light may beattenuated or completely blocked from exiting the volume of the screwconveyor sterilizer 1600 by radiation attenuating baffles (not shown) onthe infeed (i.e. receiving) end 1672 of the screw conveyor sterilizer,and also on the discharge end 1676. Note that such baffles may besubstantially similar to any one of the embodiments of UVC attenuatingbaffles 1191 described hereinabove.

[0188] FIGS. 15A-15D show various alternative cross sectional end viewembodiments of the screw conveyor sterilizer 1600 showing variouslifting tumbler 1620 configurations. The tumblers 1620 between theflights 1616 of the auger assembly 1608 lift and tumble the foodstuff115 in the presence of the UVC light indicated by the arrows directedoutwardly from, e.g., the reflector/lid assembly 1636 and from the UVCemitters 161. Note that in some embodiments, there is a reflector 1688that is substantially distinct from the trough lid 1692 (which alsofunctions as a UVC attenuating baffle.

[0189] The retention time of the food product 115 in the screw conveyorsterilizer 1600 is substantially determined by the following values: theauger assembly 1608 rotational speed, the auger pitch (i.e., the augerpitch is the distance between the flights 1616, which defines the lengthof food product 115 movement with each revolution of the auger shaft1612), and the auger assembly length. Accordingly this retention timesubstantially determines the time that any particular food product itemmay be exposed to the UVC light. It is believed that for most foodproducts 115 and operational configurations of the screw conveyorsterilizer 1600 that a UVC exposure time for each item of the foodproduct should be within the range of from 2 seconds to 60 seconds.Moreover, the following values determine the amount of UVC energy (inmicrowatts-second per centimeter squared) that may be utilized forsterilizing the food product 115 passing through the screw conveyorsterilizer 1600: the amount of UVC energy emitted by the UVC emitters161 (adjusted for the emitter ambient operating temperature and distancefrom the emitters to the food product), the retention time of the foodproduct in the screw conveyor sterilizer 1600, and the surface area ofthe food product 115 exposed to the UVC light.

[0190] In one preferred embodiment, the UVC emitters 161 are attached ina fixed position to a frame portion (not shown) of the lid/reflectorsubassembly 1636 with one or more quick disconnect pin connectors 1696(FIG. 6 or FIG. 11) for performing maintenance on the UVC emitters,e.g., removal and cleaning, or replacement. The screw conveyorsterilizer 1600 may include UVC attenuating baffles surrounding anyportions of the sterilizer 1600 where UVC light may likely escape intothe environment surrounding the sterilizer. Note that either of theelectrical coupling embodiments 169 and 169A may be also used with thesterilizer 1600. In particular, these electrical couplings allow theemitters 161 to be easily removed and manually cleaned during sanitizingactivities in a food processing plant, while providing a watertightelectrical connection if cleaned in place, or during operation of theemitters 161.

[0191] The power supplies and ballasts providing electrical power to theUVC emitters 161 of the sterilizer 1600 may be substantially identicalto those used with the drum embodiment of the surface sterilizer. In oneembodiment, such power supplies and ballasts are either remotely mountedin a water tight, corrosion resistant electrical enclosure, referred toin the industry as a NEMA 4× electrical enclosure, or enclosed in awatertight assembly as shown in FIG. 5 of the light assembly 145. Such alight assembly 145 may be constructed for the sterilizer 1600 that iswatertight and may have the emitters 161 arranged in flat (i.e.,planar), convex or concave configurations. For the UVC emitters 161 tooperate effectively in environments where the ambient temperature willvary from −40 (i.e., negative forty degrees) degrees Fahrenheit to 120degrees Fahrenheit, it is preferred that the emitters 161 be UVC lowpressure mercury single ended emitters such as those manufactured bySteril-Aire, Inc., 11100 E Artesia Boulevard, Unit D, Cerritos, Calif.90703 wherein the UVC emitters are supplied separately from the powersupplies and ballasts so that the emitters and these other electricalcomponents need not be located immediately adjacent to one another.Additionally, the UVC emitters 161 may be enclosed in a plastic material(not shown), which is applied in a shrink wrap fashion to each emitterso that the plastic material fits tightly to the emitter. Moreover, asdescribed previously, the plastic material does not substantially reduceor alter the UVC light generated by the emitters, and is of appropriatestrength to contain the glass particles in the event such an emitter isshattered. Steril-Aire Inc. single ended emitters are commerciallyoffered by Steril-Aire Inc. with or without such a plastic coating. TheSterile-Aire Inc. single ended emitters are typically available inlengths of 16 inches, 20 inches, 24 inches, 30 inches, 36 inches, and 42inches. The length(s) of the UVC emitters 161 used in an embodiment ofthe screw conveyor sterilizer 1600 may be selected to be compatible withthe length of the sterilizer 1600 and, e.g., the design of thelid/reflector subassembly 1636. Moreover, note that the Steril-Aire UVCEmitter provides from 50 watts to 70 watts of UVC radiation per emitter.UVC germicidal emitters 161 are also manufactured commercially by othercompanies, such as Aquionics, Inc. 21 Kenton Lands Road, Erlanger, Ky.41018, and American Ultraviolet 2400 W. Cape Cod Way, Santa Ana, Calif.92703.

[0192] In a similar manner to the rotating drum embodiment of theinvention, the emitters 161 (and their corresponding reflectors 1688 orlid reflective surfaces 1640) used in an embodiment of the sterilizer1600 direct the radiated UVC light in the direction of the food product115 in the screw conveyor sterilizer 1600. The UVC reflector 1688 orreflective surfaces 1640 may be manufactured of a reflective andcorrosive resistant material such as previously identified above for UVCreflector materials. In one embodiment, the shape of the UVC lightreflector 1688 or the reflective surfaces 1640 is such it directs theUVC light to the area where the food product 115 is being tumbled asshown in FIGS. 15a through 15 d. Note that the UVC light support (notshown) is typically in a fixed location and position so that thestationary UVC emitters 161 and UVC reflector 1688 (or reflectivesurfaces 1640) remain in a constant position relative to the foodproduct 115 being lifted and tumbled within the auger assembly 1608 bythe tumblers 191.

[0193] The screw conveyor sterilizer support frame 1684 (e.g., FIG. 16)includes structural support assemblies manufactured of corrosionresistant materials such as stainless steel angles or tubes, andengineered for adequate structural strength to support the imposed loadswith a minimum of deflection. The frame 1684 may be manufactured withcontinuous welds to prevent the creation of crevices in which foodparticulates and bacteria could harbor, and to allow the frame to beeasily sanitized. The support frame 1684 typically is in a stationaryposition relative to the auger trough 1604 and the rotating augerassembly 1608. Thus, the support structure 1684 typically holds theauger trough 1604 in a stationary position relative to the rotation ofthe auger assembly 1604.

[0194] Many food products 115 are weighed prior to packaging on multipleselect scales, which are common in the food processing industry, andwhich are often arranged in a circular configuration with the foodproduct 115 entering at a center area of the circular configuration. Forfood processing applications with such a circular arrangement of suchmultiple select scales, the screw conveyor sterilizer 1600 may beceiling mounted so that the discharge device 1628 of the sterilizer 1600can be located so that the food product is deposited downwardly into thecenter of the circular scale area.

[0195] Since each of the UVC light reflectors 1688 (or the or reflectivesurfaces 1640) may be designed for positioning at a fixed distance andorientation to both the associated emitters 161, and the in-trough foodproduct 115, the distance of the UVC emitters to the food product islimited by the diameter of the auger assembly 1608. That is, duringrotation of the auger assembly 1608, the auger flights 1616 are, e.g.within less than 0.125 inch clearance of the bottom of the trough 1604.Thus, the outside diameter of the auger flights 1616 define the closestthe emitters 161 can be to the centerline of the auger shaft 1612, andtherefore, to the foodstuff 115 in the bottom of the auger trough 1604,and to the foodstuff being lifted and tumbled by the tumblers 1620.

[0196] The trough 1604 and auger assembly 1608 are manufactured ofnon-corrosive material such as stainless steel, aluminum or a plastic.The inside surface of the trough 1604 and the surfaces of auger assembly1608 are preferably polished to increase the reflectivity of the UVClight within the screw conveyor sterilizer 1600. Alternatively, thetrough 1604 may have a liner with an inside surface of polishedstainless steel, polished aluminum, polished zinc, or polished coatingssuch as magnesium carbonate, nickel or chromium. Moreover, the varioussurfaces of the auger assembly 1608 may have a similar polished coating.Also, the trough 1604, auger shaft 1612, and auger flights 1616 havematerial thicknesses selected to provide adequate structural strengthfor the imposed foodstuff 115 loads that are transported through thetrough. The trough 1604 and auger assembly 1608 may be manufactured withcontinuous welds both to prevent the creation of crevices in which foodparticulates and bacteria could harbor, and to allow the screw conveyorsterilizer 1600 to be easily sanitized.

[0197] In one embodiment of the sterilizer 1600 for food products 115which are sensitive to temperature change, the trough 1604 is insulatedwith an insulation material such as polyurethane, polystyrene,fiberglass, or calcium silicate. The insulation material may be sheetedwith stainless steel on the exterior to enclose the insulation. Theinsulation is selected to minimize conductive heat transfer to theexterior of the trough 1604. As an aside, note that the drum 111 of therotating drum embodiments of the sterilizer 181 may also be similarlyinsulated.

[0198] In food processing applications with frozen products inunconditioned ambient environments, the trough 1604 may also beinsulated to prevent the sweating of the exterior of the trough 1604caused by condensation of moisture from the unconditioned ambientenvironment. Also, the trough 1604 could be jacketed and heated withresistance type electrical wire or jacketed for cooling or heating withcold thermal fluid, hot thermal fluid, or steam. In another embodiment,the trough 1604 may be manufactured of sheet metal material withperforations or holes, which serve to separate solid materials andliquid materials, and/or to allow materials of a lesser particle sizethan desired to be separated from the flow of foodstuff 115 through thescrew conveyor sterilizer 1600. Examples of food processing applicationswherein a perforated trough 1604 is desirable are: the processing of rawwhole potatoes where surface dirt is removed and the dirt is allowed topass through the perforations in the trough, and/or the processing ofvegetable products that are conveyed by the pumping of water and whereinthe vegetables are to be separated from the water by allowing the waterto pass through the perforations in the trough.

[0199] In the screw conveyor sterilizer 1600 embodiment of FIG. 16, thesterilizer is inclined relative to the hopper 1680 and receives aconsistent flow of food product 115 from a bulk supply in the hopper forirradiation by UVC light. UVC attenuating baffles (not shown) may beprovided adjacent to or surrounding the: (a) the inlet or infeed device1624, and/or (b) the discharge device 1628 for thereby: containing theultraviolet light within the screw conveyor sterilizer 1600 as a safetyfeature to protect the eyes and the skin of personnel in the area nearthe sterilizer, and/or altering such UVC light which escapes from thesterilizer 1600 so as to not cause health damage to employee eyes orskin. Additionally, the screw conveyor lid/reflector subassembly 1636 ismanufactured using UVC attenuating materials. Such UVC attenuatingmaterials include opaque metal or plastics such as are typically used aswelding curtains for similar protection of eyes and skin of personnel inthe area of the welding activity. In some embodiments of the sterilizer1600 that include a perforated trough 1604, the UVC attenuatingmaterials may be required around the entire screw conveyor sterilizer1600 for the protection of eyes and skin of personnel in the area of theultraviolet rays.

[0200] The rotational motion of the auger assembly 1608 is caused by adrive motor (not shown). There may be one or more power transmissioncomponents (also not shown) for transferring the rotation motion to theauger assembly 1608 from the drive motor. The auger shaft 1612 issupported in bearings on the auger end bells 1648 which may be supportedby the support frame 1684 as described above. The power transmissioncomponents cause motion from the drive motor to be transmitted to theauger shaft 1612 at an intended rotational speed. It is well known tothose in the food processing arts that there are various methods tocause the rotational motion of the auger assembly 1608, such as timingbelts, roller chain and sprocket drives, v belts, etc. These componentsare readily available from manufactures such as Baldor Motors andDrives, 5711 R. S. Boreham Jr. St., Fort Smith, Ark. 72908, MartinSprocket and Gear Inc., 3100 Sprocket Dr., Arlington, Tex. 76015-2828,etc. The rotational speed of the auger assembly 1608 may be adjustablefor altering the retention time of the foodstuff 115 in the sterilizer1600 being exposed to the UVC light. Rotational speed adjustment with ACelectrical three phase motors can be accomplished with variablefrequency electronic drives, which are common to those familiar with thearts. Variable frequency drives are readily available from manufacturerssuch as Allen Bradley Co. Inc., 1201 South Second St., Milwaukee, Wis.53204. The auger assembly 1608 may also be rotated at varying speedswith hydraulic motors in combination with fluid flow adjustment valves,which are common to those familiar with the arts. The auger assembly1608 may have a rotational speed range of from less than one revolutionper minute to about sixty revolutions per minute.

[0201] In operation the foodstuff 115 is deposited into the sterilizer1600 by the product infeed device 1624, thereby providing anaccumulation of foodstuff in the bottom of the trough 1604. Thefoodstuff depth in the bottom of the trough 1604 is usually below thebottom surface of the auger shaft 1612. In operation, the tumblers 1620are continuously moving with the rotation of the auger assembly 1608.Each of the lifting tumblers 1620 protrudes from a surface 1698 (FIG.14) of one of the auger flights 1616 at an angle of, e.g., approximately90 degrees to this auger surface. However, other angles in the range of15 to 90 degrees are also possible. In some embodiments, each of thelifting tumblers 1620 is substantially planer and parallel to therotational axis of the auger assembly 1608. Each of the lifting tumblers1620 may be fixedly attached to at least one the flights 1616 such thatthe lifting tumbler extends inwardly from an outermost flight edge 1700(FIGS. 14 and 15) of the auger assembly 1608 towards the shaft 1612. Inone embodiment, the lifting tumblers 1620 may be short (in the directiongenerally towards the shaft 1612), and accordingly they may not extentthe full distance to the shaft 1612, and thus such a lifting tumblerdoes not continuously span the extent from the shaft to the outsideedges 1700 of the auger flights furthest from the shaft. Assuming thateach of the lifting tumblers 1620: (a) extends from the outer edge 1700of the flights 1616 toward the shaft 1612 by at least an amountcorresponding to an expected depth of the foodstuff 115 in the bottom ofthe trough 1604, and (b) spans substantially the entire distance betweenthe two consecutive flights 1616 that the lifting tumbler is positioned,then upon rotation about the shaft 1612, each of the lifting tumblers1620 can lift substantially all the foodstuff in the bottom of thetrough 1604 between the flights which the lifting tumbler is positionedon each shaft 1612 revolution. In some embodiments of the sterilizer1600 such lifting tumblers 1620 can extend from the shaft 1612 to theoutmost edges 1700 of the flights 1616. Alternatively, there may belifting tumblers 1620 that extend towards the shaft 1612 from theoutermost edges 1700 of the auger flights 1616 only part of the expectedfoodstuff 115 depth, in which case such lifting tumblers may lift onlyan expected predetermined portion of the foodstuff in the bottom of thetrough 1604 between the flights that such a lifting tumbler ispositioned with each revolution of the shaft 1612.

[0202] For a specific food surface sterilization application wherein thesterilizer 1600 is used, the following values must be known: (i) therange in foodstuff flow rate (in weight per time increments), (ii) therange in foodstuff 115 bulk density (in weight per unit of volume), and(iii) the desired destruction rate for the most resistant anticipatedbacteria, yeast, fungi, and/or mold spores. The application combines theeffects of the auger assembly 1608 diameter, auger pitch, emitter 161and reflector surface 1640 assembly length, auger assembly rotationalspeed, and the quantity, location, operating temperature, and wattage ofthe UVC emitters 161 to provide the required UVC dosage to substantiallyall foodstuff surfaces to achieve the desired destruction rate of themost resistant anticipated bacteria, yeast, fungi and/or mold spores.

[0203] Additionally, it is important to note that embodiments of thescrew conveyor sterilizer 1600 can be controlled using a controller thatis substantially similar to the controller 1400 described hereinabovefor rotating drum embodiments of the present invention. It is believedthat given the above description of the controller 1400, one of ordinaryskill in the art can also make and use a controller for varioussterilizer 1600 embodiments. In particular, such a controller forcontrolling one or more sterilizers 1600, may be a simpler version ofthe controller 1400 in that there may be no corresponding functionalityfor changing an inclination of a sterilizer 160, and there may be nocorresponding functionality needed for sensing and determining whetherthere is a food product blockage within the trough 1604. Thus, acontroller for one or more sterilizers 1600 may be no componentscorresponding to: the drum inclination controller 1460, the druminclination sensor 1469, the drum inclining device 1468, and in-drumfood product load blockage sensor(s) 1424. However, substantially allother components of the controller 1400 may be translated intocorresponding components for a sterilizer 1600 controller by replacingthe term “drum” with “trough and/or auger assembly”, replacing the term“in-drum” with “in-trough”, and changing any numerical labeling to beconsistent with the labeling of sterilizer 1600 components of FIGS.14-16.

[0204] Moreover, it is also an aspect of the invention, that sincecontrollers for various embodiments of the invention are so similar,that a single controller may be used to control different embodiments ofthe surface sterilizer 181. Thus, such a controller may control both oneor more rotating drum embodiments, and additionally control one or morescrew conveyor sterilizer 1600 embodiments.

[0205] The following example illustrates a method for configuring andusing the screw conveyor sterilizer 1600.

EXAMPLE 3 Frozen Whole Kernel Corn in a Rotary Screw Conveyor

[0206] Frozen, whole kernel corn is to be surface sterilized prior tobeing provided to a multiple select scale unit, which is circular from aplan or overhead view. Since the food product is to be introduced to thecenter of the scale unit, the embodiment of the sterilizer 181 is anscrew conveyor sterilizer 1600 which is supported to provide forsuspending at least the discharge device of the screw conveyor above themultiple select scale. Assuming the whole kernel corn is frozen, and isbeing sterilized in an unconditioned ambient atmosphere; the trough 1604may be insulated to prevent condensation on the exterior of the trough,wherein the condensation could drip onto the whole kernel corn on themultiple select scale. The flow rate of the whole kernel corn throughthe screw conveyor sterilizer 1600 is limited by the scale to no morethan 100 weighments per minute of 1 pound per weighment, or a flow rateof 100 pounds of whole kernel corn per minute. Bulk density of the wholekernel corn is 46 pounds per cubic foot; therefore, volume flow rate is2.17 cubic feet per minute (100 lb/minute*1 ft³/46 lb).

[0207] The screw conveyor sterilizer 1600 is configured to kill 99% ofListeria monocytogenes bacteria at a dosage of 19,000microwatts-seconds/centimeter squared. At this UVC dosage, the exposuretime is expected to be 6 seconds for each surface of the tumbling wholekernel corn. UVC irradiance sterilization efficiency is reduced to 33%to assure that all surfaces of the whole kernel corn are adequatelyexposed to the UVC germicidal radiation. Therefore, the exposure cycletime for the flow of whole kernel corn through the screw conveyorsterilizer 1600 may be no less than 18 seconds (6 second exposure*1/0.33efficiency). At a volume flow rate of 2.17 cubic feet per minute, and a18-second exposure cycle time, the volume of whole kernel corn perexposure cycle is no more than 0.65 cubic feet (2.17 ft³/minute*18seconds/exposure cycle*1 minute/60 seconds). An auger assembly 1608having an auger flight 1616 diameter of 8 inches, and an UVC emitter 161lid 1636 length of 8 foot is selected, wherein there are tumblers 1620between the flights 1616 in the length of the lid 1636 with UVC emitters161. A food product average depth of no more than 3 inches is preferredto provide clearance with the center shaft 1660 of the auger assembly1608. Thus, when the whole kernel corn is being tumbled within the augerassembly 1608, it is being lifted by the tumbler 1620 on each revolutionof the auger flights 1616. At a product depth of 3 inches in the augertrough, 68% of the lower half of the trough 1604 is occupied by wholekernel corn. With the lid 1636, including UVC emitters 161, being 8 feetlong, the maximum quantity of whole kernel corn in each cycle is equalto 0.95 cubic feet (3.14*4 inches*4 inches*½*0.68*1 ft²/144 in²*8 ft).Since 0.95 cubic feet is greater than the volume of whole kernel cornper exposure cycle (i.e. 0.65 cubic feet/exposure cycle), it is believedthat the screw conveyor configuration will be adequate for the expectedflow rate of whole kernel corn. The exposure area of the whole kernelcorn in the screw conveyor sterilizer 1600 is based on the trough 1604width, the lid 1636 (with the UVC emitters 161) length, multiplied bysix times to account for the quantity of sides on the cube shaped wholekernel corn pieces, at least one of these sides exposed to UVC light atany time. The exposure area of the whole kernel corn is 32 square feet(8 inch*1 ft/12 inch*8 ft*6 times). Assume that a quantity of (8) UVCemitters 161 are selected which are 24 inches long each, wherein theseemitters are mounted within the screw conveyor lid 1636 so that they arearranged to be offset from the exposed whole kernel corn by an averageof 4 inches. Further, assume that the UVC energy level of each emitter161 is 50 watts, and that this energy level is de-rated to 80% energyfor the refrigerated ambient temperature inside the screw conveyorsterilizer 1600 caused by the flow of the frozen whole kernel corn, andadditionally de-rated to 58% due to the distance from the emitter to theexposed whole kernel corn. Therefore, effective energy contacting thewhole kernel corn after the cumulative adjustments for temperature anddistance is 23.2 watts/emitter (50 watts/emitter*0.8 temperaturederate*0.58 distance derate), or total 185.6 watts from the 8 emitters.Thus, UVC energy for irradiating the whole kernel corn is approximately37,460 microwatts-seconds/cm² (185.6 watts*6 seconds*{fraction (1/32)}ft²*1 ft²/929 cm²*1,000,000 uw/w) resulting in a safety factor of 2.0for the target 99% kill rate of Listeria monocytogenes. Inclinationangle and drum rotational speed are adjusted so that the whole kernelcorn indeed flows through the screw conveyor with a 24 second exposurecycle time. Accordingly, with the application of the surfacesterilization process provided by the screw conveyor sterilizer 1600immediately before the packaging of the whole kernel corn, any bacteriathat contaminated the surface of the whole kernel corn will be killed orinactivated at a 99% destruction rate. Therefore, the potential forwhole kernel corn waste, recall from market, bio-terrorism and consumerillness from consumption of contaminated whole kernel corn is greatlyreduced. In recent years, improvement in the testing and detection ofbacteria in foodstuffs have provided for the detection of much smallerconcentrations of bacteria; therefore, due to increasingly smalleramounts of detected bacteria, there has been increased cost to the foodprocessing industry associated with product waste, recalls, and consumerclaims. The present invention as demonstrated in this examplesubstantially solves surface contamination of food products.

[0208] The foregoing discussion of the invention has been presented forpurposes of illustration and description. Further, the description isnot intended to limit the invention to the form disclosed herein.Consequently, variation and modification commiserate with the aboveteachings, within the skill and knowledge of the relevant art, arewithin the scope of the present invention. The embodiment describedhereinabove is further intended to explain the best mode presently knownof practicing the invention and to enable others skilled in the art toutilize the invention as such, or in other embodiments, and with thevarious modifications required by their particular application or usesof the invention.

What is claimed is:
 1. An apparatus for processing foodstuff comprising:a transport having an entry and an exit different from said entry,wherein a food product enters said transport via said entry and moves tosaid exit; one or more germicidal emitters for emitting a germicidal sothat said germicidal inactivates one or more micro-organisms on surfacesof the food product in said transport, wherein said germicidal emittersare capable of withstanding a plurality of water sprays having pressuresof up to 1,400 psig, and at temperatures up to 210 degrees Fahrenheitwithout said emitters failing due to one or more of water or heat damagesubstantially resulting from said sprays; an assembly for securing atleast some of said germicidal emitters in a predetermined arrangement,wherein said assembly with its secured emitters is moveable between afirst position wherein said secured emitters are operable forinactivating the one or more micro-organisms on surfaces of the foodproduct in said transport, and a second position wherein said securedemitters are substantially inoperable for inactivating the one or moremicro-organisms on surfaces of the food product in said transport;wherein said second position is a preferred assembly position for one ormore of: cleaning said assembly, cleaning said secured emitters,detaching an emitter from said assembly, securing an emitter to saidassembly; and one or more moveable tumblers for contacting the foodproduct in said transport, wherein movement of said tumblers lift thefood product in said transport so that the food product tumbles withinsaid transport while the food product in said transport is exposed tosaid germicidal.
 2. The apparatus of claim 1, wherein germicidalemitters are capable of withstanding water sprays approximately no morethan 1,350 psig.
 3. The apparatus of claim 1, wherein the water spraysare approximately 1,250 psig.
 4. The apparatus of claim 1, whereingermicidal emitters are capable of withstanding water spraysapproximately no more than 200 degrees Fahrenheit.
 5. The apparatus ofclaim 1, wherein the water sprays are approximately 195 degreesFahrenheit.
 6. The apparatus of claim 1 wherein the said transportincludes a drum for rotating the food product, wherein said entryincludes a first end of the drum and said exit includes a second end ofthe drum.
 7. The apparatus of claim 6, wherein said drum includes atleast one of said tumblers is attached to an interior surface of saiddrum.
 8. The apparatus of claim 7, wherein said at least tumblerincludes a projection that extends from said drum interior surfacetoward an axis of drum rotation.
 9. The apparatus of claim 8, whereinsaid projection also extends from a first end substantially adjacent tosaid entry to a second end substantially adjacent to said exit.
 10. Theapparatus of claim 8, wherein said projection has a spiral shape betweensaid first and second ends.
 11. The apparatus of claim 9, wherein saiddrum has a downward inclination from said entry to said exit.
 12. Theapparatus of claim 6 wherein said tumblers rotate with a rotation ofsaid drum.
 13. The apparatus of claim 7 wherein said tumblers areattached an interior circumference of said drum.
 14. The apparatus ofclaim 6, wherein at least one of said tumblers includes at least onerecess on an interior of said drum, wherein said recess extends awayfrom an axis of drum rotation
 15. The apparatus of claim 14, wherein across section of said drum interior has a polygonal shape and saidrecess includes a vertex of the polygonal shape.
 16. The apparatus ofclaim 6 further comprises a drive mechanism for providing a rotationalmotion to said drum, wherein said drive mechanism includes one of anelectric, hydraulic, and pneumatic motor for operatively rotating anbelt about an exterior of said drum.
 17. The apparatus of claim 1,wherein said germicidal includes one or more of radiation, light waves,sound waves, and ozone.
 18. The apparatus of claim 1, wherein saidgermicidal is ultraviolet light in the C wavelength band.
 19. Theapparatus of claim 1, wherein said emitters are sleeved with a plasticfor containment of glass in said emitters.
 20. The apparatus of claim 1,wherein said emitters are capable of food product surface sterilizationat a temperature of −40 degrees Fahrenheit.
 21. The apparatus of claim 1further including one or more germicidal attenuating baffles foreffectively preventing said germicidal from exiting from a predeterminedvolume, wherein said baffles are sufficiently close to said transport sothat personnel adjacent to said transport but outside said predeterminedvolume are not exposed to an unsafe amount of said germicidal.
 22. Theapparatus of claim 1, wherein an exposure of said germicidal to saidfood product surfaces does not substantially increase the temperature ofsaid food product when said germicidal inactivates one or moremicro-organisms on surfaces of the food product in said transport. 23.The apparatus of claim 1, wherein an application of said germicidal tosaid food product surfaces does not substantially alter a flavor,texture, color, or other eating characteristics of said food product.24. The apparatus of claim 1, wherein said food product includes rawpotatoes for thereby reducing at potato spoilage.
 25. The apparatus ofclaim 1, wherein said food product includes one of: a spice, an herb,grains, nuts, rice, a cereal, crackers, a dehydrated food product,potato chips, corn chips, pork rinds, beefjerky, and a quick frozen foodproduct.
 26. The apparatus of claim 24, wherein said quick frozen foodproduct includes one of: corn, peas, carrots, whole potatoes, dehydratedpotatoes, figs, peppers, French-fried potatoes, beef crumbles, beeftrimmings, fajita meats, and shrimp.
 27. The apparatus of claim 1,wherein said food product includes a fresh food product.
 28. Theapparatus of claim 27, wherein said fresh food product includes one of:potato dices and shreds, carrots, asparagus, broccoli, cauliflower,onions, brussels sprouts corn, peas, cucumbers, lettuce, beans, grains,beef, chicken, fish, shrimp, herbs, fruits, blueberries, cranberries,peeled and unpeeled tomatoes.
 29. The apparatus of claim 1, wherein saidgermicidal does not include a sterilizing chemical.
 30. The apparatus ofclaim 1, wherein the tumbling of the food product does not causesubstantial breakage of the food product.
 31. The apparatus of claim 1,wherein at least one of said tumblers is replaceable by a tumbler havinga different shape or size.
 32. The apparatus of claim 1, wherein saidgermicidal reduces at least one of mold, fungi, bacteria, yeast, and theegg and/or larva of insects.
 33. The apparatus of claim 1, wherein thesaid transport includes a screw conveyor including an auger assembly forconveying the food product from said entry to said exit.
 34. Theapparatus of claim 33 wherein said screw conveyor includes at least oneof said tumblers between flights of the auger.
 35. The apparatus ofclaim 34 wherein the said at least one tumbler includes a projectionthat is attached to and extends from one of said flights towards an axisof rotation for said auger assembly.
 36. The apparatus of claim 34wherein said at least one tumbler rotates with a rotation of said augerassembly.
 37. The apparatus of claim 33 wherein said screw conveyor hasa downward, level, or upward inclination from said entry to said exit.38. The apparatus of claim 33 further comprises a drive mechanism forproviding a rotational motion to said auger assembly, wherein said drivemechanism includes one of an electric, hydraulic, and pneumatic motorfor operatively rotating said auger assembly.
 39. The apparatus of claim33, wherein said at least one tumbler is fastened between said flights.40. The apparatus of claim 33, wherein said germicidal includesultraviolet light in the C wavelength band.
 41. The apparatus of claim33, wherein said assembly for securing at least some of said emittersexposes the food product to said germicidal within the transport forthereby reducing at lease one of mold, fungi, bacteria, yeast, and theegg and/or larva of insects.
 42. The apparatus of claim 1 furtherincluding a controller for performing one or more of the followingactions: (a) regulating an amount of the food product entering thetransport, wherein said controller uses data indicative of an amount offood product in said transport, said data dependent upon sensorinformation related to an amount of food product in the transport; (b)obtaining germicidal information indicative of an amount of saidgermicidal required from said germicidal emitter for inactivating apredetermined amount of the micro-organisms, whereby said controllerdetermines information for identifying an amount of the germicidal foremission by said germicidal emitter; (c) outputting one or more signalsfor changing a rate of movement of said tumblers for maintaining apredetermined degree inactivation of the micro-organisms; (d) outputtingone or more signals for changing an inclination of said transport formaintaining a predetermined degree inactivation of the micro-organisms;(e) predicting an amount of the food product which will be in thetransport at a future time, wherein said controller uses sensor dataindicative of an amount of food product being moved to said entry; (f)preferring a first germicidal emission rate to a second germicidalemission rate, wherein said first germicidal emission rate is obtainedin response to a user input for setting a germicidal emission rate forthe germicidal emitters, and said second germicidal emission rate is notobtained in response to input from the user for setting a germicidalemission rate for the germicidal emitters, and wherein said secondgermicidal emission rate is used when said user input is not provided.43. The apparatus of claim 42, wherein said controller performs at leastmost of the actions (a) through (f).
 44. An apparatus for processingfoodstuff comprising: a transport having an entry and an exit differentfrom said entry, wherein a food product enters said transport via saidentry and moves to said exit; one or more germicidal emitters foremitting a germicidal so that said germicidal inactivates one or moremicro-organisms on surfaces of the food product in said transport; oneor more moveable tumblers for contacting the food product in saidtransport, wherein movement of said tumblers lift the food product insaid transport so that the food product tumbles within said transportwhile the food product in said transport is exposed to said germicidal;and a controller for performing one or more of the following actions:(a) regulating an amount of the food product entering the transport,wherein said controller uses data indicative of an amount of foodproduct in said transport, said data dependent upon sensor informationrelated to an amount of food product in the transport; (b) obtaininggermicidal information indicative of an amount of said germicidalrequired from said germicidal emitter for inactivating a predeterminedamount of the micro-organisms, whereby said controller determinesinformation for identifying an amount of the germicidal for emission bysaid germicidal emitter; (c) outputting one or more signals for changinga rate of movement of said tumblers for maintaining a predetermineddegree of inactivation of the micro-organisms; (d) outputting one ormore signals for changing an inclination of said transport formaintaining a predetermined degree of inactivation of themicro-organisms; (e) predicting an amount of the food product which willbe in the transport at a future time, wherein said controller usessensor data indicative of an amount of food product being moved to saidentry; (f) preferring a first germicidal emission rate to a secondgermicidal emission rate, wherein said first germicidal emission rate isobtained in response to a user input for setting a germicidal emissionrate for the germicidal emitters, and said second germicidal emissionrate is not obtained in response to input from the user for setting agermicidal emission rate for the germicidal emitters, and wherein saidsecond germicidal emission rate is used when said user input is notprovided.
 45. The apparatus of claim 44 further including a data storagethat includes, for each of a plurality of different food products, anamount of the germicidal to be emitted by said emitters for inactivatinga particular degree of one or more micro-organisms on the surface of thefood product.
 46. The apparatus of claim 44, wherein said controllerperforms at least some of the actions (a) through (f).
 47. The apparatusof claim 44, wherein said controller performs at least most of theactions (a) through (f).
 48. The apparatus of claim 44, wherein saidcontroller performs all of the actions (a) through (f).
 49. Theapparatus of claim 44, wherein at least one of said tumblers isreplaceable by a tumbler having a different shape or size.
 50. Theapparatus of claim 44, wherein said transport includes a drum throughwhich the food product passes, and said apparatus further includes adrive mechanism for rotating said drum with the food product therein.51. The apparatus of claim 44, wherein said controller determineswhether a request for reconfiguring said apparatus is safe to bothpersonnel within a proximity of the apparatus, and sterilizes the foodproduct to a predetermined degree.
 52. A method for surfacesterilization of one or more food products, comprising: firstdetermining a size for a food product transport having an entry and anexit different from said entry, wherein a food product enters saidtransport via said entry and moves to said exit; wherein said transportincludes one or more tumblers for contacting the food product in saidtransport, wherein movement of said tumblers lift the food product insaid transport so that the food product tumbles within said transport;second determining at least one of a quantity and configuration of oneor more emitters of a germicidal relative to the food product in saidtransport, wherein said germicidal inactivates one or moremicro-organisms on a surface of the food product in said transport;wherein said first and second determining steps are dependent upon atleast some of (a) through (f) following: (a) a rate at which a foodproduct is provided for surface sterilization; (b) an amount of thegermicidal to be emitted by said emitters for inactivating a particularquantity of one or more micro-organisms on the surface of the foodproduct; (c) an amount of the germicidal to which the food product isexpected to be exposed in said transport; (d) an elapsed time that anindividual item of the food product is expected to be in said transport;(e) a shape and a density of the food product; (f) a temperature of thefood product.